Citation
Development process for improving irrigation water management on farms

Material Information

Title:
Development process for improving irrigation water management on farms
Series Title:
Water management technical report
Creator:
Skogerboe, Gaylord V.
Lowdermilk, Max K.
Sparling, Edward W.
Hautaluoma, Jacob E
Colorado State University -- Water Management Research Project.
Place of Publication:
Fort Collins Colo
Publisher:
Water Management Research Project, Engineering Research Center, Colorado State University
Publication Date:
Language:
English
Physical Description:
4 v. : ill. ; 28 cm.

Subjects

Subjects / Keywords:
Water resources development -- Developing countries ( lcsh )
Irrigation -- Developing countries ( lcsh )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Bibliography:
Includes bibliographical references.
General Note:
"Prepared under support of United States Agency for International Development, Contract AID/ta-C-1411."
Funding:
Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
Statement of Responsibility:
prepared by Gaylord V. Skogerboe ... [et al.].

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University of Florida
Holding Location:
University of Florida
Rights Management:
The University of Florida George A. Smathers Libraries respect the intellectual property rights of others and do not claim any copyright interest in this item. This item may be protected by copyright but is made available here under a claim of fair use (17 U.S.C. §107) for non-profit research and educational purposes. Users of this work have responsibility for determining copyright status prior to reusing, publishing or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder. The Smathers Libraries would like to learn more about this item and invite individuals or organizations to contact Digital Services (UFDC@uflib.ufl.edu) with any additional information they can provide.
Resource Identifier:
50330356 ( OCLC )

Full Text



































'0 P f I I Wt M on Farms


PROBLEM IDENTIFICATION MANUAL


Prepared by
Water Management Research Project Staff


Water Management
Technical Report No. 65B


~.4, o/"


WO&I
WA








Development Process for Improving
Irrigation Water Management on Farms



PROBLEM IDENTIFICATION MANUAL


WATER MANAGEMENT TECHNICAL REPORT NO. 65B

Prepared under support of
United States Agency for International Development
Contract AID/ta-C-1411
All reported opinions, conclusions or
recommendations are those of the
authors and not those of the funding
agency or the United States Government.




Prepared by

Max K. Lowdermilk
William T. Franklin
James J. Layton
George E. Radosevich
Gaylord V. Skogerboe
Edward W. Sparling
William G. Stewart


Water Management Research Project
Engineering Research Center
Colorado State University
Fort Collins, Colorado 80523


March 1980








PROBLEM IDENTIFICATION MANUAL


PREFACE


This manual is designed as a resource for identification of farm
system constraints on irrigated agriculture. Information contained in
this manual will provide a means for determining what components of the
system are not functioning adequately to achieve improved crop
production goals. The farm water management system, the focus of this
manual, has strong interrelationships with various subsystems. As
shown in the idealized description of a farm irrigation system
(Figure 1), definite physical boundaries are delineated. The first major
boundary is the canal itself which is linked to the total irrigation
system including storage, diversion, and drainage facilities. The
drainage system is another physical boundary that demarcates the farm
irrigation system. Within the farm system there are physical boundaries
including conveyance channels, farm fields, irrigation basins, and
drainage ditches.
The farm irrigation system is also an open system since it is linked
with not only the larger physical irrigation system, but with many
organizations that regulate it and supply essential inputs. These
organizations include irrigation and agricultural bureaucracies, and
private and public organizations that supply essential inputs such as
credit, fertilizer, insecticides, seed, and farm equipment. Institutional
linkages also include markets and policy-oriented agencies.
The farm irrigation system is man-made. Irrigation is one of the
most significant ways man manipulates physical and human resources to
increase crop production. The purpose of the farm system is to
provide an adequate physical, chemical, and organizational environment
for the production of crops to meet basic human needs. In arid and
semi-arid climates, irrigation is usually required to grow crops, and
on-farm water management is often the greatest constraint to increased
agricultural productivity.
This manual provides a systematic set of procedures for describing
and analyzing the system in relationship to this purpose. A description







-- Canal -


Water Supply and Removal
Supply rates
Conveyance
Quality of water
Water removal
Precipitation
Salinity
Waterlogging


/


Farm Management Practices
Cropping patterns
Crop varieties
Cropping practices
Irrigation practices
Crop inputs
Harvesting
Storage
Marketing
Application rates
Water use


1


Drainage Channels


Institutional Linkaes I-------------
lInstitutional LinkaqesI


Rules and regulations
Price policy
Revenue payments
Markets
Roads-transportation
Input services
Credit
Water law


SPlant Environment
Temperature
Climate
Topography
Soil physical conditions
Biological factors
Soil chemical factors
Insect and weed control
Rodent-animal protection
Natural hazards



S/

- /


Extension
Cooperation
Information networks
Social norms


Figure 1.


Idealized sketch of a farm irrigation system.








of the system and its operation is developed initially from quantitative
measurements defining the operational parameters of each of the four
major subsystems. These subsystems include the plant environment,
farm management practices, water supply and removal, and the
institutional linkages as shown in Figure 1.
Several specialists are involved in analyzing the farm system. The
engineer measures the efficiency of water distribution, adequacy of
volume and rate of water supply, water use, water removal, water
dependability, and other aspects. The agronomist is concerned with all
the factors that influence the plant environment and measures these
factors in relationship to their impact on crop yields. The economist
identifies the levels of resource input and output for crop production
and farm income. The sociologist identifies the decision-making
processes of the farm manager and social factors such as behavior
norms, institutional restraints, knowledge status, and information
transfer processes that influence farmer decision-making. The
perspectives and methods of each discipline are utilized cooperatively to
establish a quantitative and qualitative description of each of the four
major subsystems and the total operation of the farm water management
system.
Information presented in this manual is designed around the four
major subsystems: the plant environment, farm management practices,
water supply and removal, and institutional linkages. Additionally,
Chapter I provides a description of the manual and its use. Chapter II
discusses problem identification. Chapters III through VI provide field
procedures for describing and identifying problems in each of the four
subsystems. Chapter VII discusses the analyses applied to the data
collected under the four subsystems and the interpretation of these
analyses.









Development Process for Improving
Irrigation Water Management on Farms



PROBLEM IDENTIFICATION MANUAL


ABSTRACT


Problem Identification is the first of three phases in the
development process with the other phases being the Development of
Solutions and Project Implementation. The Problem Identification phase
consists of two subphases; namely, Reconnaissance and Problem
Diagnosis. The Reconnaissance subphase consists of: setting
preliminary program objectives; developing a general overview of the
irrigation system; conducting reconnaissance field investigations of the
plant environment, farm management practices, water supply and
removal, and institutional linkages; preparing a preliminary listing of
problems; and refining the program objectives. The Problem Diagnosis
subphase consists of: designing diagnostic studies; conducting-
diagnostic field studies; analyzing and interpreting the findings;
identifying criteria for the selection and ranking of problems according
to program objectives; and reporting findings of priority problems and
their apparent causes.










TABLE OF CONTENTS


CHAPTER I, DESCRIPTION AND USE OF THE MANUAL .

ORIGIN OF THE MANUAL .............

NEED FOR PROBLEM IDENTIFICATION . .

STRUCTURE OF MANUAL . . . .

GLOSSARY OF IMPORTANT TERMS . .

CHAPTER II, THE PROBLEM IDENTIFICATION PROCESS

PURPOSE AND OBJECTIVES ............

RATIONALE . . . . .

MAJOR BENEFITS .................

CONCEPTS IN THE PROBLEM IDENTIFICATION
APPROACH . . . . .

Systematic Approach .............

Management Approach ............

Interdisciplinary Approach . . .

On-Farm Client Focus ............

Barriers to Problem Identification . .

THE PROCESS . . . . .


Sequence of Major Activities ..

Setting Preliminary Objectives .

Reconnaissance Overview of the System

Preliminary Listing of Problems .

Refining Objectives ..........

Designing Diagnostic Studies . .

Conducting Diagnostic Field Studies

Data Analyses and Interpretation .

Criteria for Ranking Priority Problems

Reporting the Findings . .

CHAPTER III, THE PLANT ENVIRONMENT .

CROPS AND CROPPING PATTERNS .

Crop Inventory . . .

Crop Stands . . .. .

Crop Damage . .. . .

Potential and Actual Yields . .

Crop Quality and Nutritional Value .


Page


2

3

4

5

. 10

. 10

. 10

. 12


. 13

. 13

. 14

. 16

. 18

. 19
. 3
. 4

. 5

. 10

. 10

. 10

. 12


. 13

. 13

. 14

. 16

. 18

. 19

. 20


. . 20

. . 20

. . 22

S . 23

. . 24

. . 25

. . 25

. . 28

. . 31

. . 32

. . 34

. . 34

. . 36

. . 36

. . 37

. . 37

. . 37









TABLE OF CONTENTS
(continued)



SO ILS . . . . . . .
Soil Nutrient Supply ............ .....
Visual Observations .. ... .. .. . ... .
Tissue Tests . . . . . .
Paint and Spray Tests ................
Imbalances and Toxicity ................


Page
37
37
38
40
42
42


Chemical Soil Tests .. .. ..... ... ... 42
General Fertility Guidelines . . . 42
Plant Analyses .... ............... 43
Physical and Chemical Properties of
Soil and Root Zone ... ... .. .. .. .. 43
Subsoil Properties .. . . . 44
Topography ... .. .... .... ...... 44
CLIMATE . . . . . .. 44
CHECKLISTS . . . . . .. 44
INTERDEPENDENCY OF PLANT ENVIRONMENT WITH
FARM MANAGEMENT PRACTICES . . .... .50
Case Study . . . . . .. 50
CHAPTER IV, FARM MANAGEMENT PRACTICES . .. 53
IRRIGATION PRACTICES ................. 53
Farm Water Use Efficiency . . .... .55
Crop Water Use ..... ............ 59
Open-Pan Evaporation . . ... 60
Other Devices for Measurement of
Evaporation ... .. .. ... ... ..... 60
Calculation from Weather Observation
Data . . . . . ... .60
Lysimeters .. . ... . . 61
Irrigation Timing ...... .............. 61
Field Observations .... ........ . 61
Calculations of ETp and ETa from
Existing Data . . . . 64
Field Measurements. . .. .. 64
Tensiometers, Gypsum Blocks, or
Fiberglass Blocks .. ... .... ...... .64










TABLE OF CONTENTS

(continued)


Gravimetric and Neutron Probe
Moisture Measurements .

Irrigation Timing as a Function


of ET Estimates .
CROPPING PRACTICES .....

Cropping Patterns . .

Crop Rotation ...

Crop Mixes ..... ...

Polyculture .. ......

FARM BUDGETS . . .

Farm Management Inventory

Resource Inventory .....

Land . . .

Labor . . .

Capital . . .

Animals . . .

Water Inventory ......

Outputs . . .

Decision-Making Environment

InterdeDendencv with Farmer'


INTERDEPENDENCY OF FARM MANAGEME
WITH WATER SUPPLY AND REMOVAL

CHAPTER V, WATER SUPPLY AND REMOVAL

CLIMATE . . . .

Climatic Data . . .

Solar Radiation .......

Air Temperature ......

Relative Humidity . .

Wind Speed .........

Open-Pan Evaporation ..

Rainfall and Distribution .

Weather Observation Stations .

Water Supply Problems .


Page


64


. . . . 65

. . . . 65

. . . 65

. . . . 65

. . . 65

. . . 65

. . . 68

. . . 68

. . . . 68

. . . .. 68

. . . 78

. . . . 78

. . . . 78

. . . . 78

. . . . 78

. . . 79

s Community .. . 79


NT PRACTICES
SUBSYSTEMS 79

. . 81

. . . 81

. . . 81

. . . 81

. . . 83

. . 83

. . . 84

. . 84

. . 84

. . 84

. . 84









TABLE OF CONTENTS
(continued)


Page
85


Ground Water Recharge Problems


Irrigation Requirements . . .. 85
Crop Adaptation Problems . . .... 85
Climatic Hazards ........... ........ 86
WATER AND SALT BUDGETS . . . .. 86
IRRIGATION WATER ... . . 88
Source and Availability . .. ... 88
Precipitation ............... .. .. 88
Surface Flows, Reservoirs, and
Dams . . . . . 89
Groundwater Pumpage and Recharge .. . 89
Water Quality ......... ........... .. 90
Existing Water Quality Data . . .. 91
Field Spot-Checks .... .......... .. 91
Individual Sample Analyses . . .. 91
Silt Burden. .. . . . 91
Mineral Ion Content (TDS) . . 91
Polluted Water . . . . 92
Composited Samples .... ............ 92
Water Suitability for Irrigation . . .. 92
COMMAND AREA . . . .. . 92
Topography ........ ............. 93
Land Capability ............. ....... 93
Cropping Patterns ......... .. .... ... .93
Field Size and Levelness .............. 94
Location of General Features. . . .. 94
WATER REMOVAL ..................... 95
Root Zone Salt Balance. . . .. . 95
Aeration Requirements . . . .. 96
Workability of Lands .. ............. 97
Sources of Drainage Water . . . 98
Evidence of Drainage Problems . . ... 98
CHECKLISTS . . . . . .. 99








TABLE OF CONTENTS
(continued)

Page
INTERDEPENDENCY OF WATER SUPPLY AND
REMOVAL SUBSYSTEMS WITH INSTITUTIONAL
INFRASTRUCTURE . . . .... .99
CHAPTER VI, INSTITUTIONAL LINKAGES ... .. .... 105
WATER IRRIGATION LINKAGES . . .... .105
Policies ...................... 105
Laws, Codes, and Regulations . . .... .105
Organizations . . . . . 107
Linkages . . . . . 107
AGRICULTURAL INFRASTRUCTURE . . ... 107
Agriculture and Water Organization . .... 108
Research and Extension ............... 108
Agricultural Input Services . . .... .109
Marketing and Transportation . . .... .109
Credit Institutions ................ .. .110
Cooperatives . . . . . 110
Communication and Information Networks ...... 110
Farmer Perceptions of Institutions . ... .111
SOCIO-CULTURAL NETWORK . . .... .111
The Setting for Social Control . ... ..... .114
Territoriality . . . . 114
Size ... .. ... .............. .. 114
Tim e . . . . . 114
Facilities . . . . . 114
Elements for Social Action . . ... .114
Cultural Elements .... ............ 114
Norms . . . . .115
Sanctions ........ ......... 115
Beliefs ................... 115
Sentiments . . . . 115
Goals . . . .... 116
Structural Elements . .... ...... .116
Status-Role . . . .. 116









TABLE OF CONTENTS
(continued)


Page


Characteristics of the
individual . . .
Capacity of the individual . .
Processes for Social Action . . .
Communication ..............
Boundary Maintenance . . .
Systemic Linkage ............
Social Control . . . .
The Resulting Social Action . . .
Individual Decision-Making
Environment .. .. ... .. ..
The Collective Decision-Making
Environment .. .. .. ... .. .
Format for Irrigation Studies . . .
SUMMARY . . . . . .
CHAPTER VII, DATA ANALYSES AND INTERPRETATION
INTERDEPENDENCE OF SYSTEM COMPONENTS .
PROBLEM DIAGNOSIS ANALYSES . . .
Plant Environment . . . .
Farm Management Practices . . .
Irrigation Practices . . .
Farm Budgets ..............
Water Supply and Removal . . .
Climatic Analysis ............
Water and Salt Budgets . . .
Cropland Diversions ...........
Root-Zone Flows .............
Groundwater Model . . .
Available Models .............
Institutional Linkages ............


NI INTERPRETATION OF F S


. 116
. 116
. 116
. 117
. 117
. 117
. 117
. 117

. 118

. 118
. 119
. 119
. 126
. 126
. 129
. 131
. 131
. 131
. 135
. 136
. 136
. 139
. 141
S. 141
. 145
. 147
. 147
. 148


COMPLETION OF PROBLEM IDENTIFICATION PHASE


..








TABLE OF CONTENTS
(continued)

Page
REFERENCES . . . .... ... .151
APPENDICES . . . .... ... .156
EQUIPMENT NEEDS .................. 157
DATA MANAGEMENT AIDS . . .... .160
SELECTION, TRAINING, AND EVALUATION OF
FIELD WORKERS .................. 166
EXAMPLE FORMS FOR FARM BUDGET ANALYSIS .. 178









LIST OF FIGURES


Figure Page
1 Idealized sketch of a farm irrigation system ... iii
2 Diagram showing the farm level learning dimensions
of researchers and farmers .. .... . ... 19
3 Flow diagram of sequential activities in the Problem
Identification phase . . .. . 21
4 Idealized sketch of the plant environment .. 35
5 Idealized sketch of a farm irrigation system and
farm management practices . .... .. 54
6 Schematic of instrumentation required for on-farm
hydrology investigations . ... . 56
7 Schematic of the hydrologic variables to be
considered in an on-farm subsystem investigation 57
8 Schematic of constant water-table lysimeter .. ... 62
9 Schematic of the construction of a hydraulic
weighing lysimeter .. .. ......... .. 63
10 Example of agricultural land use mapping . 66
11 Idealized sketch of a farm irrigation water supply
and removal subsystem ........ ...... 82
12 Idealized sketch of the institutional infrastructure
for a farm irrigation system .. ... . 106
13 Flow diagram for data analyses and interpretation
of findings ........ ... .......... 127
14 Interdependence of irrigation system components
and program objectives . ... .. . 128
15 Factors affecting levels of living of farmer clients 128
16 Flow diagram for Problem Diagnosis analyses . 130
17 Procedure for the evaluation and improvement of
irrigation systems .. .. ... ... .. 132
18 Categories of irrigation performance for individual
application . . . . . 134
19 Example of monthly and annual frequency distribution
for precipitation and temperature ... ... 137
20 Comparison of lysimeter data and the Penman equation
estimate for alfalfa in 1975 . ... .. 140
21 Schematic of a generalized hydro-salinity model 142
22 Illustrative flow chart of the root-zone budgeting
procedure .......... ............ 144


xiii








LIST OF FIGURES
(continued)

Figure Page
23 Flow chart of the groundwater modeling
procedure . . . . . 146
24 Interpretation of findings from the Problem Diagnosis
analyses . . . . . 149









LIST OF TABLES


Table
1 Glossary of terms . . .
2 Checklist of problem identification activities for use
by the program team manager . .
3 Basic requirements for successful teamwork .
4 Activities checklist for designing problem
identification (P.I.) studies . . .
5 Outline of selected types of data collected by one
discipline and utilized by another discipline .
6 Criteria for ranking priority problems . .
7 General fertility guidelines for some nutrients .
8 Checklists on reconnaissance methods for crops and
cropping patterns and soils . . .
9 Checklists on detailed diagnostic methods for crops
and cropping patterns and soils . .
10 Hypothetical case study of symptoms and causes of
nitrogen deficiency . . . .
11 Definitions of cropping intensity . . .
12 Format for inventories of actual practices for major
crop s . . . . . .
13 Checklists on reconnaissance inventory for farm
management practices . . . .
14 Checklists on detailed diagnostic methods for farm
management practices . . . .
15 Checklists on reconnaissance methods for water
supply and removal ..............
16 Checklists on detailed daignostic methods for water
supply and removal ...............
17 Major organizations related to water supply and
rem oval . . . . .
18 Format of major sociological categories affecting the
decision-making process of individuals . .
19 Format of sociological components affecting the
irrigation behavior of a farmer . . .
20 Checklists on reconnaissance methods for
institutional linkages ... .. .. .. .. .. .
21 Checklists on detailed diagnostic methods for
institutional linkages . .. . .


Page
S6

S. 15
S. 17

S. 26

S. 29
31
S. 43

S. 45

S. 48

S. 51
S. 67

69

S. 71

S. 74

. 100

. 102

. 104

S. 113

S. 121

. 122

. 124








CHAPTER I


DESCRIPTION AND USE OF THE MANUAL


This manual is designed to provide a flexible set of guidelines,
concepts, procedures, and methods for identification of factors that may
inhibit efficient functioning of farm irrigation systems. Procedures are
provided for a systematic approach to objective evaluation of existing
farm irrigation systems. This is done as preparation for a systematic
search for socio-technical solutions to problems that may occur.
The authors have extensive experience in research and
development related to irrigation systems, and are well aware that
irrigation systems have unique physical, social, economic, and legal
characteristics that have complex interdependencies. While irrigation
systems have many "site-specific" factors that must be analyzed indivi-
dually, there are procedures that can be utilized for understanding
general problems.
This manual provides several aspects that should be considered in
evaluating a farm irrigation system. The factors and methods of inves-
tigation described can serve as a checklist to emphasize important
variables that may require systematic examination if adequate data do
not already exist. This manual is designed to provide guidance in
developing an understanding of water management constraints in
irrigated agriculture.
The flexible systematic approach for evaluating existing farm
irrigation systems explained in this manual will help delineate priority
research needs and improvements. A major assumption is that all
irrigation systems can be greatly improved in terms of efficiency and
increased benefits to farmer-clients. However, there are several
aspects that will not be covered in this manual. This manual DOES
NOT PROPOSE:

To provide a universal technique that can be used without
adaptation to specific situations.

To provide guidelines to study problems that are simply
interesting to the particular investigators.

To provide a guide for the identification of all problems of
any irrigation system.








To provide guidance for surveys that are so comprehensive
they are of little use to applied researchers and practitioners.

To assume to do more than serve as a flexible guide to
practitioners and researchers who have the task of improving
complex farm irrigation systems.


ORIGIN OF THE MANUAL

The authors have intensively studied their own assumptions and
approaches regarding irrigation systems. They have determined there
is a need for using a more objective and systematic approach. Their
approach was field tested in Pakistan with respect to research and
development activities. A theoretical framework, A Research-
Development Process for Improvement of On-Farm Water Management1
has been developed and should be consulted by the reader.
This manual of procedures and methods is the first phase of a
much larger team effort2 in describing the development process for
improving irrigation water management on farms. Manuals have been
prepared to provide procedural guides for each of the three phases:

I. Problem Identification

This combines an interdisciplinary approach with farmer
participation to achieve an understanding of system operation.
Results of this method are an objective, quantitative definition
of priority problems.3

II. Development of Solutions

The interdisciplinary staff combines knowledge and experience
with systematic research to develop acceptable solutions to
priority problems. Applied, adaptive, and evaluative
research methods are also used under farmer conditions for
the assessment of solutions. These results are used to define
solution packages.


Clyma, Wayne; Max K. Lowdermilk; Gilbert L. Corey, 1977. A
Research-Development Process for On-Farm Water Management. Water
Management Technical Report No. 47, Colorado State University,
Fort Collins.
2William Franklin and William Stewart, Agronomy; Gaylord Skogerboe
and Doral Kemper, Engineering; Ed Sparling, George Radosevich, and
Warren Smith, Economics; Max Lowdermilk, Dave Freeman, and James
Layton, Sociology; and Jack Hautaluoma, Psychology.
3op. cit p. 8.
op. cit. p. 8.








III. Project Implementation

A development project evolves when decision-makers select a
solution package for implementation. Trained personnel use
the carefully designed technological package to work directly
with farmers to solve their problems.


NEED FOR PROBLEM IDENTIFICATION

Those concerned with improving farm irrigation systems around the
world should not have to be convinced of the need to identify problems
systematically. In the past, however, many problems have usually been
identified in this manner.
Financial resources are now being allocated to solving the problems
of irrigation water management. Previously, few systematic approaches
to evaluate existing irrigation systems, analyze weaknesses and failures,
and prescribe technologies for improvement were developed. Usually,
each system that was evaluated became an individual case study.
Improvement programs were developed within a short time period
utilizing little more than the experience of the project leader.
Frequently, these improvements treated symptoms rather than real
problems. Such conventional approaches generally ignore the farmer,
his attitudes, his knowledge, and his constraints. Previous approaches
have not resulted in sufficient significant improvements at the farm
level.4
Water management improvement is important because there are an
estimated 200 million acres of land presently under irrigation. New
areas are being added at the rate of less than 10 million acres annually.
Many irrigation systems operate at relatively low levels of water use
efficiency and at low levels of production.5 Thus, a major need is for
the improvement of existing systems for the following reasons:

To conserve water supplies by improved management for rapid
increases in food production;

To improve the return on investments of existing systems;


4Wiener, Aaron. 1972. The Role of Water in Development. McGraw-Hill
Book Co., New York, p. 422.
5Bos, M. G. and Nugteren, J. 1974. International Institute on
Irrigation Efficiencies, Pub. No. 19, International Institute for Land
Reclamation and Improvement, Wageningen, The Netherlands.








To reduce the costly waterlogging and salinity problems that
are often symptoms of poor management;

To identify the methods small farmers can use to increase net
agricultural productivity by participating in new production
possibilities;

To reduce the need for large capital investments in new
systems; and

To gain knowledge that can provide new criteria for the
development and management of other systems with a focus on
participation of farmer-clients.

A concerted effort to improve irrigated agriculture, if focused at
helping the subsistence farmer having small landholdings, could bring
improved income and living conditions to a substantial percentage of the
world's disadvantaged.

The cost of expanding the present 85 million irrigated
hectares by 90 million hectares is estimated at $130,000
million. This is not only exceedingly costly, but also a slow
process because projects from design to completion often take
10 to 12 years. Investments in new projects will continue but
more quick yielding programs seldom improve the efficiency of
farm water use, therefore, the focus in the years ahead must
be given to farm-level problems. There is much exciting
drama in building large structures but we must not forget the
small and often tragic dramas that take place daily on millions
of small holders' farms where water conservation is a matter
of success and failure and even life and death.6

STRUCTURE OF MANUAL

This manual is designed for quick reference and each chapter is
delineated below.
Chapter II answers three basic questions about problem
identification. These questions are:

Why do problem identification studies?
What is the problem identification process?
How is problem identification done?

Chapters III through VI provide both reconnaissance procedures
and detailed diagnostic methods for the examination of factors related
to:

6World Bank, 1975. The Assault on World Poverty, John Hopkins
University Press, Baltimore, Maryland, pp. 95-96.








The Plant Environment (Chapter III)
Farm Management Practices (Chapter IV)
Water Supply and Removal (Chapter V)
Institutional Linkages (Chapter VI)

In each of the four chapters special factors are discussed along with
the suggested reconnaissance and detailed diagnostic procedures and
methods for use in field investigations. The most important factors
have been included; however, there are likely others that the readers
will want to add for their site-specific situation. Checklists are
provided at the end of Chapter III through Chapter VI for convenience.
The reader is encouraged to utilize this checklist to determine if all
essential factors have been covered.
After each major section the factors of one section are related to
those of the next section. For example, the last section of Chapter III
shows how optimal plant growth factors relate to farm management
practices which are the subject of Chapter IV.
Chapter VII provides a description of the interdependence of the
four subsystems in a problem identification study, with a focus on the
importance of close project staff collaboration. The analyses applied to
the data generated from the diagnostic field studies are discussed,
along with the interpretation of these analyses.
This is followed with appendices that provide several aids for the
field manager including:

Equipment needs;
Data management aids;
Selection, training, and evaluation of field investigators; and
Example forms for farm budget analysis.

In addition to this manual, there is a series of technical field
methods published by the Egypt Water Use and Management Project at
Colorado State University through funds from the USAID. These are
referenced in this text for easy referral by the field workers.


GLOSSARY OF IMPORTANT TERMS

Important concepts and definitions utilized throughout the manual
are provided. While there can be much debate about certain








definitions, the definitions in Table 1 represent the authors intent when used
in these manuals.

Table 1. Glossary of terms.


Term


Definition


Action Research







Adaptive Research



Agronomic Subsystem


Applied Research




Communication


Conflict Resolution





Economic Factors


A systematic investigation conducted
specifically for a defined program
which does not conclude with data
collection, but leads eventually to
project implementation. Testing is
conducted under the conditions of
the recipient of the research.

A systematic investigation to fit new
technological advances into different
environments.

A system that utilizes the resources
of soil, solar energy, and water in
combination with necessary inputs to
create an adequate environment for
the growth of crops of the types and
amounts required.

The direction or utilization of
knowledge to the improvement or
change of specific materials or
conditions.

The transmission of thoughts, ideas,
and information from one individual
or group to another individual or
group.

The process where disagreement
among members of the research staff
is confronted and a decision is made
on how that disagreement will be
resolved.

The allocation or utilization of all
physical, chemical, biological,
human, and organizational resources
in such a way as to maximize
economic and social goals from farm
production efforts as determined by
individual decision makers and public
policy.











Evaluative Research







Farmer-Client


Farm Water Management


Interdisciplinary Approach








Management Focus


The process in which the scientific
method is consciously applied for the
purpose of making a judgment about
the value of methods, processes, and
programs about which there is
concern utilizing various types of
data, decision rules, and criteria.

The focus of a research project that
encourages the concentration of the
researchers to be centered on the
farmers and also develops proper
attitudes towards working with
farmers.

Water management in agriculture
is the process by which water is
manipulated and used in the
production of food and fibers.
Water management is how water
resources, irrigation facilities laws,
farmers, institutions, and proce-
dures in soil and cropping systems
are used to provide water for plant
growth. It encompasses all water
used for that purpose including
irrigation and water from natural
precipitation.

An approach where different
academic disciplines are combined to
examine a research problem. The
output of the study consists of an
integrated approach where each
discipline considers the effects of
the other disciplines in analysis and
recommendations.

Recognization by the researchers
that a farmer is a decision-maker,
and that the operation of the farm
results from a rational approach of
identifying a problem, developing
alternative solutions and imple-
menting the solution on the farm.
Any recommendations by the
research group must be analyzed as
to the consequences.











Problem Identification






Reconnaisance





Research Team


Social Subsystem






Systems Approach







Team Building


Water Application Process


The procedure through which the
understanding of an irrigation
system is attained in order to define
specific shortcomings that prevent
the irrigation system from being
fully effective in its operation.

Preliminary observations of an area
which allows researchers to obtain
general information to serve as a
means for providing an initial
direction for research activity.

Individuals who work together on a
research problem.

The social and organizational
supports at the macro- and micro-
levels needed for successful manip-
ulation of the farm irrigation system
to achieve desired individual and
collective goals over time.

A research approach with the
objective to study all the components
pertaining to a specific research
problem. With respect to irrigation
management, such aspects would
include physical and institutional
properties.

The process in which individuals
involved in a research program
change from single purpose inves-
tigations by each participant to an
integrated study involving the
contributions of all the participants.

A process to supply desired amounts
of water uniformly to meet the needs
of seed germination, plant
emergence, salinity control, soil
physical conditions, erosion,
aeration, temperature, and surface
drainage in a manner to adequately
grow crops.











Water Delivery System


Water Removal System





Water Use Requirements


A system to convey water from the
supply source to the fields to be
irrigated at the proper time, volume,
and flow rates required for the
cropped area considering losses
occurring within the system based
upon design criteria.

A system to maintain proper salinity
levels, physical soil conditions (for
root aeration and workability of
soil), and to reduce health and
environmental hazards.

The adequate supply of water at the
proper times in the quantity and
quality necessary for crops to
maintain acceptable levels of soil
salinity, soil-air temperature, and
soil physical conditions for crop
growth.









CHAPTER II


THE PROBLEM IDENTIFICATION PROCESS


PURPOSE AND OBJECTIVES

The goal of the Problem Identification phase is to understand the
traditional farming system and isolate the major constraints that inhibit
its adequate functioning. It is assumed the purpose of the system is to
increase agricultural production, improve the standard of living for all
classes of farmers, and to conserve natural resources. The objectives
of the Problem Identification phase are:

1. To provide a systematic approach for understanding the farm
irrigation system,

2. To identify constraints that inhibit agricultural production,

3. To identify constraints that impede the progress of small
operations,

4. To provide output from the Problem Identification phase as
input to the Development of Solutions phase, which requires
more intensive research, and

5. To provide data that can be utilized within a short period of
time (one or two irrigation seasons) depending on the
particular conditions and needs of the Problem Identification
phase.


RATIONALE

There are several important reasons why increased attention should
be given to problem identification studies of irrigation systems in low
income nations. These reasons are listed below:

1. Little is known about the content and structure of traditional
farming systems,

2. Valid empirical farm-level data for systematic planning of
research is typically not available,

3. There is always a danger of treating problem symptoms rather
than causes in dealing with complex farming systems, and

4. Most available research covers a limited subject area that
generally neglects systems problems.








Special focus in problem identification is given to listening to the
farmer-clients, understanding their needs, and their perceptions of
major farm constraints. This procedure helps build credibility with the
farmers by increasing their awareness and interest in solving farm
problems. Farmers' perceptions often provide useful insights into the
problems. Second, without listening to the farmer it is unlikely that
one will gain an understanding of how the farming system actually
works. If development programs are to be successful, more under-
standing of how traditional farming systems work is necessary.
The role of the farmer has a central focus in the Problem
Identification phase. Basic assumptions made about the farmer are
listed.

1. The farmer is central to the irrigation system.

2. The farmer is rational in decision-making with respect to the
constraints.

3. Traditional farmers will respond positively to improved
technologies that are technically sound, economically
profitable, and culturally compatible.

4. Farmers will participate in improvement projects that
demonstrate visible and tangible results if positive and
concerted efforts are made to develop credibility by including
farmers in the planning and evolution of these programs.


MAJOR BENEFITS

A major benefit derived from the Problem Identification phase is
understanding the system as composed of many interdependent factors.
Answers must be found for such questions as: What are the system
boundaries? What is the system supposed to do? How well does it
function? What are the critical components of the system and how do
they interact? What components are not functioning adequately? Since
the farmer is an important aspect of the system, information must be
obtained about what he does, why he does it, and what are the results.
A second benefit is the objective identification of major problems
that inhibit increased crop production based on empirical field data.
All problems cannot be included; therefore, it is necessary to focus
upon significant crop production problems. Stated criteria are used for








ranking problems in relationship to their importance in limiting crop
production. Both quantitative and qualitative methods of ranking are
used.
Other benefits include provision of empirical data for input into
the solution phase, provision of data for use in the evaluation of the
program, participation of the farmer, procedures for developing and
maintaining credibility with farmers, opportunity to train host country
personnel in interdisciplinary procedures for problem identification, and
saving of time and other scarce resources.
There are always pressures in research and development programs
to provide fast results for anxious host country officials and donors.
Time spent in the Problem Identification phase is, time saved in the
Development of Solutions phase, as one researcher has suggested.

Difficulty in isolating the problem is often due to the
tendency to spend a minimum of effort on problem definition
in order to get on to the important matter of solving it.
Inadequately defining the problem is a tendency that is down-
right foolish on an important and extensive problem-solving
task. A relatively small time spent in carefully isolating and
defining the problem can be extremely valuable both in illumi-
nating possible simple solutions and in ensuring that a great
deal of effort is not spent only to find that the difficulty still
exists--perhaps in greater magnitude.


CONCEPTS IN THE PROBLEM IDENTIFICATION APPROACH

Problem identification is the combination of an interdisciplinary
team approach with active farmer involvement to achieve an under-
standing of how the farm irrigation system operates and to identify in a
systematic and objective, manner a quantifiable definition of system
problems. Clyma, Lowdermilk, and Corey (1977) has a detailed
explanation of this process.


Systematic Approach

The problem identification process is one. that is systematic in
contrast to a fragmented approach. Because of the complexity of the



10Adams, J. L. 1974. Conceptional Blockbusting; A Guide to Better
Ideas. W. H. Freeman and Co., San Francisco, CA, p. 14.








farm irrigation system with its physical, biological, legal,
organizational, and social characteristics it is impossible for single
researchers to understand adequately or describe the system by
focusing on single components, or to identify their interactions. The
problem identification approach requires researchers who plan carefully
and work closely together to establish preliminary objectives, do field
reconnaissance, and design and implement diagnostic field studies.
Research efforts must include coverage of the whole farm irrigation
system, and not simply those aspects that someone assumes are
important (Table 2). Teamwork is highlighted for all major activities
and this requires good management if the process of problem
identification is to produce the desired results.


Management Approach

The emphasis throughout this manual is MANagement. This
concept is used in two particular ways. First, the focus and objective
of the Problem Identification phase is to ascertain the effectiveness of
the management of the present system. This requires understanding
the system from the position of the farmer. Often the complex task of
managing all the factors related to the farm system is not fully
appreciated. Unlike the specialized roles of individuals in industry, the
farmer must perform the role of cultivator, buyer, seller, bookkeeper,
along with other functions. The complexity of the farmer's management
tasks is shown in Figure 1. It should be noted that some of these
factors can be controlled by the farmer while others cannot be
controlled by the farmer. This makes management even more complex
and creates extreme risks for the decision-maker.
Researchers should attempt to understand the farmer's situation as
they investigate farm problems. This perspective will help the project
staff recognize that problems involved in farming systems are multi-
dimensional and require a strong interdisciplinary approach. No one
discipline or single researcher can hope to comprehend these complex
interrelationships alone; therefore, a group approach is the only
reasonable method that will produce results.








Table 2. Checklist of problem identification activities for use by the
program team manager.

Preparation for Problem Identification Studies
Selection of investigators
Selection of a team leader
Team building training
Discipline training in field methodologies
Setting of objectives of problem identification studies
Gaining an Overview of System
Identification of available research
Discussion with officials from relevant organizations about their view
Obtain maps and other relevant resources
Development of checklists of possible problem areas
Development of lists of other people to contact
Organization of Initial Field Visits
Criteria for field sites to visit
Responsibilities of team members for initial field visits
Logistics for initial field visit
Implementing Initial Field Visits
Visits to farms
Observation methods for all team members
Nonstructured interviews with farmers and those who work with
farmers directly
Selected measurements
Team collaboration and preparation of preliminary report on initial
field visits
Establish criteria for selection of sample sites for formal problem
identification studies
Design of Detailed Diagnostic Field Studies
Decisions on site selection
Develop objectives for problem identification
Decisions on methodologies
Design and test survey instruments
Design selection criteria for field workers
Establish responsibilities for all field workers
Design evaluation methods for field workers
Develop checklist for equipment needs and logistics
Establish time frame for problem identification studies
Establish data management plans
Implement Formal Investigation
Develop required maps
Develop methods for data quality control and field supervision
Collect data
Analyze and interpret data
Write team report on findings
Rewrite report for selected audiences
Establish Criteria for Selection
Clarify assumptions used
Clarify quantitative or qualitative methods
Rank problems in terms of criteria








This leads to the second dimension of management. Just as the
farm manager must coordinate many factors, the manager of individual
researchers must know how to manage the staff effectively. Without
good management, there is the danger of individual researchers doing
what they prefer. Without careful coordination, collaboration, and
communication, it is doubtful if problem identification investigations will
result in either an understanding of the complex farm system problems
or an identification of the priority problems that require solutions
(Table 2 shows some of the activities a group leader must coordinate).
The program leader (also called team leader, group leader, team
manager, or program manager in this text) is in a position similar to
the farm manager. While not directly responsible for each activity
listed, the program leader must make decisions about all these factors.
However, many of these decisions can be delegated to others. Unlike
the farmer who learns through long experience, very few administrators
of interdisciplinary research groups have had either long experience or
training. Where possible, special training should be obtained.
The sequence of activities in Table 2 is not inflexible; however,
the team manager is responsible for their execution. This guide or
checklist can be used by the manager to direct all staff to a systematic
approach in the Problem Identification phase.


Interdisciplinary Approach

Problem identification requires an effective interdisciplinary
research staff to understand the farm irrigation system. Along with
technically qualified, experienced professionals in the disciplines
required, other essential components are commitment to the project,
management skills, open communication, and close collaboration of team
members with each other and with the farmers. Perhaps the three most
essential elements for effective interdisciplinary teamwork along with
expertise include respect for the contributions that each discipline can
make; desire to establish effective communication with all disciplines and
farmers; and the desire to learn from each other and from farmers in
particular.
Ideal requirements for successful teamwork is listed in Table 3. It
may seem impossible to find experts with these qualifications. However,










Table 3. Basic requirements for successful teamwork.


Requisites

Commitment


Management


Checklist of Attributes


Expertise in discipline
Broad training and experience
Respect for contributions of
other disciplines
Flexibility
Emotionally mature and secure
Demonstrated ability to work
well on teams
Committed to interdisciplinary
research
Commitment to farmer-clients
Willingness to learn

Demonstrated management abilities
Skills in program planning
Skills in conflict resolution
Skills in task assignments
Gives attention to detail
Ability to communicate
Does not favor a single discipline
Evaluation skills
Ability to communicate and
skills in human relations
Incentive system design

_ Open communication, no hidden
agenda
Regular staff meetings for planning
Communication feedback utilized
Communication to and from clients
Communication to and from all team
members
Communication to and from officials

Goal setting
Developing a framework and design
of study
_ Agreement on methodologies
Selection of sample
Problem-solving
Evaluation of work
Data management plans
Analysis of data and reporting


Communication








Collaboration


__


--








this ideal list provides goals that can be obtained over time if the staff
are willing to communicate, learn, and appreciate each other and their
disciplines.


On-Farm Client Focus

The problem identification approach, unlike many research
approaches, provides strong focus on the farmer and the farm system.
Actions in any portion of the Problem Identification phase are developed
from farm level data without prior assumptions about farm problems.
Assumptions too often dictate research and development efforts.
The Hadith, one of the Holy Books of Islam, for example, provides
a significant statement about learning that relates to problem identifica-
tion studies at the farm level. It is translated as "if there is
knowledge in China, go there and learn." The authors of this manual
are saying to all researchers, "there is knowledge at the farm level and
from the farmer; go there and learn how the farm irrigation system
works." To use an arabic term to stress the point, a true Talib Elm
(Arabic for "seeker after knowledge"), will search for knowledge at the
farm level and from the farmer and not try to find an easy way out.
This strong focus on farm level conditions and the farmer-client is an
important concept for problem identification studies.
Problem Identification should be viewed as a learning experience.
A simple diagram emphasizing mutual learning on the part of the farmer
and the researcher is presented in Figure 2. Unless the environments
of the researcher and the farmer are properly linked, learning is
inhibited. Unless the research situation is geared to the real farm
situation, it is unlikely that the farmer can be significantly helped by
researchers.
The analogy of the doctor-patient can also be used to indicate the
importance of mutual learning. The doctor (researcher) examines the
physical condition and asks significant questions of the patient (farmer)
in order to understand his particular situation. The farmer provides
knowledge of his condition in order that a diagnosis is possible. The
researcher then provides the farmer with knowledge drawn from his
diagnostic skills to assist the client. If this analogy is accepted as
basic to the Problem Identification phase, then the general principles
listed below should prevail throughout the process.








Environment Communication Environment
Research Farm
Situation Understanding Siarmion
Situation_ Situation
Knowledge Knowledge
and Mutual Learning and
Experience Experience




Figure 2. Diagram showing the farm level learning dimensions of
researchers and farmers.

1. Problem Identification should include all disciplines required,
as well as farmer-clients to assure that a systems approach is
utilized.

2. Problem Identification should be task-oriented, rather than
oriented toward prestige maintenance of one discipline over
another. Each discipline is necessary and one discipline is no
more important than another.

3. Problem Identification should be educational for researchers
and clients and lead to greater understanding of the farm
system and its subsystems.

4. Problem Identification should be experimental in that it is
never final in the research and development process. At
stages other than problem identification, the researchers may
have to search for sources of problems ignored earlier.

Barriers to Problem Identification

There are several barriers that cause researchers to disregard the
basic learning model of the Problem Identification phase. These
barriers have been identified often by observation of researchers at
work. These are as follows:

1. Inability to see the farming community as a system,

2. Inconsistency of the researcher's image of how the system
should work with how it actually does,

3. Lack of interaction and communication among researchers in
planning for problem identification,

4. Impatience in identifying the real problems first before
solutions are determined,

5. Inability to appreciate contributions from other disciplines,








6. Assumption that the "expert" should know what the problem
is and how to solve it without verification in a specific field
situation,

7. Lack of appreciation of the local culture which clients have
acquired and lack of acceptance of the clients' role in
decision-making,

8. Assumption that development problems can be solved quickly
by applying more technology without considering the social
factors, and

9. The lack of understanding and sensitivity to cross-cultural
differences that exist between researchers and farmers and
among farmer-clients.


THE PROCESS OF PROBLEM IDENTIFICATION

To accomplish problem identification it is necessary to understand
the sequence of major activities including reconnaissance field
investigations, designing diagnostic studies, conducting diagnostic field
studies, analyzing and interpreting findings, and selecting criteria for
ranking significant problems.


Sequence of Major Activities

The systematic approach of the Problem Identification phase
includes some overlap of activities. This does not mean, however, that
activities are random or to be conducted as separate procedures.
Experience indicates there is a general sequence of events that can be
delineated. The sequence of the major activities that can be used for
problem identification studies is shown in Figure 3.


Setting Preliminary Objectives

First, there is a need for clearly stated preliminary objectives.
The preliminary objectives may, for example, be similar to the
following:

1. To gain an understanding of how the organization of the
system and the conditions of the situation influence farm
decisions,

2. To identify the major physical, biological, socioeconomic, and
organizational constraints in the farm system that limit
agricultural production, and








PROBLEM I1D:f!TIFICATIO

PRELIMINARY PROGRAM OBJECTIVES
a. Increased Agricultural Production
b. Increased Equity of Income Dihiij',ir:j
c. Resource Conservation


DEVELOP GENERAL OVERVIEW OF SYSTEM|


CONDUCT RECONNAISSANCE FIELD INVESTIGATIONS
a. Plant Environment
b. Farm Management Practices
c. Water Supply and Removal
d. Institutional Linkages


PRELIMINARY LISTING OF PROBLEMS


REFINE PROGRAM OBJECTIVES


DESIGN DIAGNOSTIC STUDIES


CONDUCT DIAGNOSTIC FIELD STUDIES
a. Plant Environment
b. Farm Management Practices
c. Water Supply and Removal
d. Institutional Linkages


ANALYSES AND INTERPRETATION OF FINDINGS


IDENTIFY CRITERIA FOR SELECTION AND RANKING
OF PROBLEMS ACCORDING TO PROGRAM OBJECTIVES


REPORT FINDINGS OF PRIORITY PROBLEMS
AND THEIR APPARENT CAUSES


Figure 3.


Flow diagram of sequential activities in I.he
Problem Identification phase.


t








3. To provide an understanding and overview of the system and
its problems to provide input for the design of more detailed
diagnostic studies.

These preliminary objectives are such that they provide definite
focus to the researchers involved. The focus is on the farm,
constraints to agricultural production, and developing a preliminary list
of problems that may need to be considered for the diagnostic field
studies.


Reconnaissance Overview of the System

The reconnaissance phase or overview of the farm system is a
basic learning situation that provides an opportunity to increase the
general understanding of the farm situation. This includes the acquisi-
tion of background information from previous research that should be
summarized. An agronomist, for example, will need information on
climate, soils, current soil-water-crop management practices, and levels
of current yields. Visits should be arranged with selected officials of
organizations related to agriculture, such as governmental departments
and universities; and selected personnel at research institutes. Staff
must remember in such visits, however, that there is usually an
"official view" that may or may not completely represent the realistic
view. Project members involved in the reconnaissance should remain
objective and reserve their views until empirical field data documents
the real problems.
Reconnaissance activities also include informal interviews with
selected farmers. These interviews should seek information about the
farmer's views concerning crop production levels and constraints,
management practices, economic conditions, and sociological aspects of
the operation. Experience in Pakistan and Egypt has shown the number
of researchers approaching the farmer should be relatively small to
avoid intimidating the farmer. Questions should be carefully prepared
in advance to obtain useful information. Also, those who interview
farmers should be prepared and skilled in interview techniques.
Information obtained from the farmer should be compared to that
provided by officials and research stations by staff who should conduct
meetings at the end of each day's activities.









Reconnaissance also includes preliminary field surveys, which
should not be confused with the more detailed diagnostic surveys
conducted later. The preliminary field survey is designed to provide
an understanding and overview of the farm system and general areas
where more intensive focus may be needed in the detailed survey.
At this stage selected field investigations will focus on the plant
environment, farm management practices, water supply and removal,
and institutional linkages. For example, the agronomist will want to
gain an understanding of the general soil and water conditions, the
growth status of various crops, and current cropping practices.
Likewise, the agricultural engineer may want to learn about current
irrigation practices, flow rates, drainage problems, and other factors.
Prior to visiting the field the staff should have compiled sufficient
background information combined with their own expertise and
experience to develop a list of things to observe or questions to ask.
For example, the agronomist may want to observe plant growth char-
acteristics and experience in that area will help determine if growth is
normal or abnormal. The agronomist may want to observe "above
ground characteristics" such as the status of plant nutrition, water
relationships, pest infestation, or weeds. The agronomist may also
want to make observations of root systems, crop stands, physical soil
characteristics, and current crop management practices.
Individuals on the staff will collect preliminary data for planning
the detailed field studies. However, it is possible to collect too much
data or information at this stage. Information should be obtained from
farmers about their fields, selected individuals who work directly with
farmers, and officials. Information about the farm situation should be
used to prepare a more detailed or diagnostic field study.


Preliminary Listing of Problems

The general information obtained from the initial field
reconnaissance should be discussed in detail by team members who will
propose a preliminary list of problem areas that may require intensive
investigation. This can be done by referring to the preliminary objec-
tives that provide criteria for selection of major problem areas. These
criteria may include factors that limit crop production and the








productive capacity of small farmers, factors that inhibit the improved
well-being of farmers, the conservation of soil and water resources, or
other criteria established by the government, a funding agency, or
staff members. It is important to be clear about the criteria because
there must be priority in the areas that can be examined within limited
resources of time, personnel, and funds.
A careful listing of priority problems that emerged from the
problems identified on the farm system is much better than designing
the diagnostic studies from unfounded ideas and assumptions that
reflect only the interests or biases of researchers or officials of a
funding agency.


Refining Objectives

The research team and officials of relevant agencies should then
refine the preliminary objectives with respect to the knowledge gained
from the reconnaissance field investigations. These objectives should
be more clearly stated and specific than the preliminary objectives. For
example, these objectives may include some of the following:

1. To make diagnostic studies of conveyance and field water
application losses.

2. To determine the constraints of waterlogging and salinity on
crop production.

3. To determine the constraints farmers face with regard to
supplies of essential inputs.

4. To determine the constraints of present water codes and
regulations on farmers' irrigation practices and maintenance of
the farm irrigation system.

5. To determine the fertility problems in relationship to crop
production levels.

6. To rank the major constraints to improved crop production for
all classes of farmers for the Development of Solutions phase.

This brief listing is indicative of only some possible objectives for the
more intensive diagnostic field studies.








Designing Diagnostic Studies

The next step is to design the diagnostic field studies. It cannot
be stressed too strongly that this activity requires close collaboration
with all concerned along with sufficient time to do a good job. Time
utilized effectively in design of the field studies will be saved in
producing good results.
A checklist is provided in Table 4 which shows some of the
detailed activities involved in both the reconnaissance and the problem
diagnosis subphases of problem identification (Figure 3). This list does
not include every activity involved; however, it provides a method for
the planning process. Those activities marked by an asterick (*)
usually require team decisions and actions.


Conducting Diagnostic Field Studies

The detailed field studies are implemented to confirm constraints in
crop production, some of which may have been tentatively identified in
the informal reconnaissance field investigations. For example, more
detailed measurements may be needed to ascertain yield and quality of
crops.
Collaboration among the staff is required throughout the field
studies. Just as there has been careful cooperation in the reconnais-
sance studies and the design of the more detailed diagnostic studies,
there must be continued teamwork in the collection of field data. There
is a tendency for researchers to work individually and become involved
only with their particular activities. While various individuals will have
specific tasks to perform, many of the field activities overlap and are
the mutual responsibilities of two or more staff members. Close
cooperation is also needed because the data and the work output of one
discipline is required by another. For example, maps will be used by
all for the collection and recording of data. If the engineers develop
or obtain a base map of farm irrigation sites to be studied, this map
can be copied and made available for crop surveys, soil surveys,
topographical surveys, cross sections, slope and length of the convey-
ance system, location of outlet structures, field ditches, drainage
channels, recording groundwater fluctuations, farm size distribution,
irrigation basin size, farm ownership patterns, tenure patterns, lan'









Table 4. Activities checklist for
studies.


Sequence


designing problem identification (P.I.)


Activities


Preparation for P.I.
studies







Obtaining a general
overview of system









Organization of
initial field visits







Implementing initial
field visits









Prepare preliminary
list of problems


*Selection of investigators
*Selection of a team leader
*Team building training
Discipline training in field
methodologies
*Setting of priority objectives
for reconnaissance


Identification and review of
available research
*Discussions with selected
official/organizations
*Obtaining maps and other
relevant resources
*Develop initial checklists of
information needed
*Maintain current list of people
to contact


*List objectives of visits
*Establish criteria for field sites to
visit
*Determine responsibilities of each
team member
*Review checklists
*Examine logistics


*Visit farms
*Encourage observational methods for
all team members
*Conduct nonstructured interviews
Selection of measurements
*Team collaboration on findings for
each day
*Establish criteria for PI site
selection


*Team collaboration
*Devise criteria for selection of
problems
*List problems
*Consult with all parties concerned








Table 4. (continued).


Sequence

Design of diagnostic
field studies


Activities


*Decide on site selection
*Develop PI objectives
Design and test survey
instruments
*Determine methodologies
*Select criteria for field workers
*Establish responsibilities for field
workers
*Design and: implement field
workers' orientation
*Design evaluative methods for
field workers
*Design checklist of equipment needs
*Determine logistics
*Set-time frame
*Determine data management plans


*Denotes collaborative decision making.








fragmentation, and other important data. In other words, cooperation
is not only essential, it is also a condition for successful interdisci-
plinary research in problem identification.
An example of the method by which group members might identify
the data collected by one discipline which would be used by another
cooperating discipline is shown in Table 5. It is obvious from the list
that while all the data collected are used by the staff as a whole,
certain types of data provided by disciplines with certain expertise are
provided to other team members. This type of cooperation should occur
throughout data collection activities to provide quality data without
duplication and overlap.


Data Analysis and Interpretation

After the data are collected, data analysis and interpretation must
be completed as a cooperative activity. Data analysis must be carefully
planned at the time of design of the field studies if it is to provide
useful findings. Most often data management including analysis is not
planned adequately until after data are collected when it may be too
late. Individual researchers may know how they will analyze their
data; however, they seldom know how the data of several disciplines
will be analyzed.
For example, a researcher would want to know what major factors
influence the yields of specific crops in an area. Data may be available
from field studies on fertilizer use, seed rates, water applications,
sowing dates, and farmer extension contacts from several of the partic-
ipating disciplines. In order to run a multiple regression or a stepwise
regression, these data have to be from the same farms and of a quality
that can be correlated. The point is that it is never sufficient to
simply have data on the above factors by the various disciplines.
Unless data are in a form so correlations can be made with the
dependent variables, many types of analyses cannot be completed. Data
must be analyzed and interpreted objectively and correctly to be useful.
In brief, data analysis should be designed so the results will
indicate the priority farm problems limiting production. To provide a
long list of problems without showing their relative relationship to each
other is not sufficient. Problems or constraints to crop production









Table 5. Outline of selected types of data collected by one discipline
and utilized by another discipline.


Primarily
Collected By Used By Types of Data


Sociologists




Sociologists
Economists





Sociologists







Sociologists






Agronomists








Sociologists
Economists


Sociologists
Engineers



Engineers
Agronomists
Sociologists
Economists



Engineers
Agronomists
Sociologists





Engineers
Agronomists
Economists
Sociologists



Economists
Engineers
Agronomists






Agronomists
Sociologists
Economists


Farmers perceptions about night
and day irrigation, major water
problems inhibiting increased yields,
solutions to major water problems

Farmer decision-making processes
related to crop decision-making,
when to irrigate a given crop, when
to stop irrigation, water lift
methods, who applies water at given
irrigation

Farmers estimations of depth of
infiltration of water, depth of crop
root system penetration, crop water
requirements, critical water demand
periods and stages of growth,
sources of major losses, magnitudes
of losses, waterlogging

Propensity of farmers to cooperate
in water lifting, trading of irri-
gation turns, farm implements
and machinery sharing, sharing of
work, patterns of both formal and
nonformal cooperation

Farm management practices: cropping
patterns and intensities; seedbed
preparation; levels of farm tech-
nologies; seed rates, quality, and
seeding methods; fertilizer inputs,
timing, amount and placement
methods; harvest methods; storage
methods

Adoption- diffusion of improved
technologies: rate of adoption, time
required for adoption, disadoption,
channels and courses of information
used at each stage in the process,
characteristics of the innovation,
farmer credibility with information
source








Table 5. (continued).


Collected By


Primarily
Used By


Types of Data


Economists




Sociologists
Economists







Engineers





Economists
Sociologists


Engineers
Economists



Economists
Agronomists
Sociologists






Agronomists
Engineers




Engineers
Economists
Sociologists


Economic returns and costs: lifting
water (alternative methods), various
crop mixes, storage systems,
transportation, marketing

Legal and organizational factors:
delivery of water to command area,
distribution of water, pricing of
water, settlement of disputes
formally and informally, farmer
interaction with river irrigation
officials, dejure compared to defacto,
sanctions, incentives

Water supply and removal:
conveyance efficiency, field applica-
tion efficiency, water quality,
consumptive use, return flow, field
topography

Information for farm decision-making:
marketing, irrigation schedules,
closures, extension, quality and
quantity of information









must be ranked in relationship to specified criteria. Examples of
criteria that may guide the analyses may include constraints to crop
production, constraints to small farmers' crop production, or levels of
living of small farmers. Quantitative analysis alone will not necessarily
provide the ranking of problems because sound judgments based upon
experience also guide the data analyses and interpretation.


Criteria for Ranking Priority Problems

The ranking of priority problems requires that specific criteria be
established. Decisions about criteria to be used may be political and
reflect the philosophy or objectives of the government, or the govern-
ment and a donor or funding organization. For example, it is assumed
that the primary goals established by the government for improvement
of farm irrigation systems are increased agricultural production,
improved rural income distribution, and improved conservation of soil
and water resources. These goals can be used as criteria for ranking
the major problems that the Development of Solutions phase will
investigate. An example of how problems might be ranked in terms of
priority are shown in Table 6.


Table 6. Criteria for ranking priority problems.


Criteria Indicators and Dependent Methods of Ranking
Variables

Agricultural 1. Yields/ha and aggregate 1. Regression analysis,
production yields analysis of variance,
team consensus

Income 2. Increased yields/ha and 2. Regression analysis,
distribution increased net income/ha cost-benefit farm
for small holders management analysis,
team consensus

Resource 3. Decreased water losses 3. Regression analysis,
conservation Decreased waterlogging cost-benefit analysis,
Decreased nitrate leaching team consensus
More productive land
made available








If increased agricultural production is the primary objective, the
major factors that significantly limit increased production will become
central to the Development of Solutions phase. If income distribution is
also a top priority by the government, the major factors that limit small
farmers' productivity will also be included. Often these factors may be
somewhat different from those that limit production on larger farms.
Finally, the judgments of the staff are also important and should
be used in ranking priority problems along with statistical analyses. It
is important to build a strong objective case for priority problems to
present to officials who otherwise might attempt to influence the
findings. Without good relationships and professional reporting in
language that can be understood, individuals who are often not sensi-
tive with local farm problems may attempt to force their conventional
wisdom on the process.


Reporting the Findings

Findings of the diagnostic field studies should be prepared for two
major audiences. Specially designed summary reports without too much
technical emphasis should be prepared for policy-makers who need to be
informed of the field studies. Often some problems identified in the
field for which only political decisions are needed for solutions will be
considered seriously by these policy-makers who need the field data for
decision-making. Also, policy-makers need empirical data for use with
internal and external organizations for funding purposes. More
technical reports are required for the Development of Solutions phase to
provide background data and benchmark data for their applied, adap-
tive, and evaluative research efforts to ascertain feasible solutions.
The chapter that follows provides the user with both
reconnaissance and detailed diagnostic procedures for investigations
related to the plant environment. Chapters III through VI contain
procedures and checklists that should be considered for investigation.
Much variation exists between countries and regions within countries as
to available data that can be used for problem identification studies.
Valid and reliable data existing for specific factors listed in Chapters
III through VI should be utilized. Variation also exists among countries








as to time and manpower available for these studies; therefore, the
manual provides procedures for both short- and long-term diagnosis on
irrigated farming systems.
A transition to the actual methods for reconnaissance and detailed
diagnostic studies are described in Chapters III through VI. Figure 1
provides an overview to the four subsystems to be covered. In
Chapter III the focus is on the plant environment, while Chapter IV is
related to farm management practices. Chapter V covers water supply
and removal, and Chapter IV discusses institutional linkages. The
reader should remember that these subsystems are closely interrelated;
however, each subsystem is examined and are treated separately in
order to more clearly present the material. Then, in Chapter VII, the
relationships between these subsystems are discussed along with
analyzing and interpreting the findings about each subsystem.








CHAPTER III


THE PLANT ENVIRONMENT


The potential crop yield is first a function of the genetic character
of the particular type and variety. The maximum attainable yield is a
function of several interdependent positive growth factors. These
growth requirements include 1) plant population (stand), 2) heat
requirement (solar radiation), 3) carbon dioxide and oxygen
requirement, 4) nutrient requirement, and 5) water requirement (soil
moisture supply). Soil serves as a physical support system, a nutrient
supply source, and a moisture storage reservoir for the crop plant.
Solar radiation along with carbon dioxide and water are basic
ingredients for producing sugars by the photosynthetic process in the
plant. Oxygen is necessary for root respiration. Crop plants have
specific requirements for nutrients, water, carbon dioxide/oxygen, and
heat. If one or more of the requirements is less than or more than
optimal, then crop production falls below the maximum attainable level.
Since optimum levels of all growth factors for all crop plants are
not available at any given time or place in the world, it becomes the
task of the farmer to manipulate, adjust, and manage all the positive
growth factors so acceptable high crop yields are obtained. In
addition, the farmer must contend with several negative growth factors.
Weeds compete with the crop for water, nutrients, and radiant energy.
Insects, diseases, and animals decrease yields or destroy crops.
Inclement weather such as frost, hail, and excessive wind cause crop
yields to be less than maximum. The delicate balance of all these
factors results in the actual yield obtained by the farmer. Thus, major
factors that need to be examined in order to identify crop production
constraints are types of crops grown, soil, climate, irrigation water,
plant protection, and cultural practices (Figure 4).


CROPS AND CROPPING PATTERNS

When the problem identification process is applied to crops and
cropping patterns, crop inventory, crop stands, crop damage, potential
versus actual yields, and crop quality/nutritional value should be









Canal

I Crops 1
-Crop inventory
-Crop stands
-Crop quality
-Crop damage
-weeds
-disease
-insect
-rodent
-animal
-herbicide
-Crop yields


Soils
-Soil nutrient supply
.-deficiency
-inbalance
-toxicities
-soil root zone
-physical properties
-chemical properties
-subsoil properties
-topography


Irrigation water
Source
Quality
Availability
Surface flow
Groundwater
Evapotranspiration
-potential
-actual
Irrigation timing


Drain


Channel


climate I
Solar radiation
Air-tempraue -------
Relative humidity
Wind speed
Evaporation
Rainfall
Crop adaptation
Climatic hazards
-wind
-flood
-frost
-hail
-high rainfall intensity


Idealized sketch of the plant envircnrernt


a-


Figure 4.








considered. A brief explanation of each of these items follows, and at
the end of this section there is a checklist of activities or methods that
can be considered when applying the problem identification process to
the plant environment. The checklist is divided into activities that
could be accomplished during the reconnaissance phase and activities
that could be considered during a more detailed problem diagnosis.


Crop Inventory

One of the first steps in determining specific crop constraints is
making an inventory of all crops grown in an irrigated area. More
detailed inventories that include acreage and total production are
usually restricted to major crops important to goals of the project. The
general inventory should include all crops because each minor crop may
not be of much importance; however, an aggregate of all minor crops
may require considerable expenditure of land, water, labor, and other
resources. The usual sequence in which crops are grown (cropping
pattern) should be included as part of the inventory. The crop
inventory is essential to determine constraints from such considerations
as agronomic, engineering, economic, legal, and social factors.


Crop Stands

The plant population must be near optimum in relation to growth
requirements if satisfactory crop yields are obtained. Optimum plant
population should be determined in the climate and culture where it is
grown. Generally, crop stands should be comparatively thinner as row
width increases and for long-season varieties.
The crop stand attained is primarily dependent upon seed quality,
proper seedbed preparation, seeding rate, method of seeding, time of
seeding, seed treatment for disease control, soil and seed temperature,
and moisture availability. Poor quality seed may contain undesirable
varietal mixtures, weed seed, plant diseases, and other crops. Poor
quality seed may also have low germination, which in turn, may be
related to overaged seed, harvesting before maturation, freezing before
maturation, heat damage, and improper storage conditions.








Crop Damage

The positive growth factors may be optimized for a given crop,
but low yields or even complete crop loss may occur from crop damage.
Crop damage may result from weeds, diseases, insects, rodents or other
animals, bad weather, and herbicides.


Potential and Actual Yields

Potential yield is defined as the amount obtained with the best
adapted crop variety grown with optimum nutrient and irrigation water
levels, and the best-known management practices with adequate plant
protection, all within the particular climatic setting. Actual yield is the
results obtained by the farmer under his particular set of conditions.


Crop Quality and Nutritional Value

Quality and nutritional value of crops should be as carefully
evaluated as the total yields. Yields of poor quality may be of less
value than lower yields of higher quality.


SOILS

In examining soils, several aspects should be considered including
the nutrient supply; physical, chemical, and biological conditions of the
root zone; subsoil properties; and topographical problems. A checklist
of reconnaissance and detailed diagnostic methods provided at the end
of this plant environment chapter will serve as a guide in problem
identification of soils.


Soil Nutrient Supply

Essential nutrient elements for most crops are considered to be the
following:
Macronutrients: Ca, Mg, K, N, S, and P
Micronutrients: Fe, C1, Zn, B, Mo, and Cu
Micronutrient requirements of plants are trace amounts.








Visual Observations

If no existing data concerning crop nutrient deficiencies and


supply is available, visual observations should be done.


Severe


nutrient deficiencies can usually be identified in the field by char-


acteristic plant symptoms.


However, symptoms cannot always be


observed at all stages of crop growth. This is especially true in the
seedling stage because a seed usually contains enough nutrients, except
nitrogen, to sustain the plant through that period.
General descriptions of nutrient deficiency symptoms are listed
according to the probability of occurrence in irrigated arid-land soils,
first for macronutrients and then for micronutrients.


Nitrogen :







Phosphorus:






Potassium:











Sulfur:


(N) Nitrogen deficiency symptoms on non-
leguminous crop plants produce a leaf of pale green
to yellow color. Nitrogen deficiency symptoms tend
to be prominent on older leaves with more severe
chlorosis followed by necrosis (death) of cells.
This results in a characteristic "firing" of the lower
leaves.

(P) Phosphorus deficiency symptoms on crop
plants are usually indicated by a general stunting
of all crop parts. Leaf color is usually a dull
greyish-green and frequently anthocyanin (red
color) accumulates in the leaf tissue and dying
leaves.

(K) Potassium deficiency symptoms on crop
plants are usually indicated by necrotic areas
starting at the tips of leaves and spreading along
the marginal edge. When N and K are simulta-
neously deficient, plants are stunted and their
leaves are small with a somewhat ash-grey color,
dying prematurely first at the tips and then along
the outer edges. The fruit or seed is small in
quantity, size, and weight. Deficiency symptoms
usually appear first on the lower leaves or plants,
progressing toward the top as the severity
increases.

(S) Sulfur deficiency symptoms on crop plants
are similar to those of N except the symptom is
characterized by uniformly chlorotic plants--
stunted, thin-stemmed, and spindly. Unlike N, S
does not appear to be easily translocated from older
to younger plant parts under stress caused by
deficiency.









Calcium:









Magnesium:











Iron:







Zinc:








Boron:






Manganese:


(Ca) A deficiency of Ca results in the failure
of the terminal buds anl the apical tip of roots of
plants to develop. As a result of these two things,
plant growth ceases. In corn, and to some extent,
cereal grains, Ca deficiency prevents emergence
and unfolding of new leaves whose tips are covered
with gelatinous material that causes leaves to adhere
to each other. This results in the classic
"ladder-effect" in Ca-deficient corn plants.

(Mg) Magnesium deficiency symptoms often appear
first on the lower leaves because it is a mobile
element and is readily trans-located from older to
younger plant parts. In most crop species, the
deficiency results in an interveinal chlorosis of the
leaf so that only the leaf veins remain green. In
more advanced stages, the leaf tissue becomes
uniformly pale yellow, and then brown and necrotic.
In some species, notably cotton, the lower leaves
may develop a reddish-purple cast that gradually
turns brown and finally necrotic.

(Fe) A deficiency of Fe shows in the young leaves
of plants. Iron does not appear to be translocated
from older tissue to the meristematic tip, and as a
result, growth is diminished. The young leaves
develop an interveinal chlorosis that rapidly
progresses over the entire leaf. In some cases, the
leaves turn completely white.

(Zn) Deficiencies of Zn have been observed in
corn; sorghum; deciduous citrus fruit, and nut
trees; legumes; cotton; and several vegetable
crops. Zinc deficiency first appears on the
younger leaves starting with interveinal chlorosis
followed by a great reduction in the rate of shoot
growth. In many tree .p~ this produces a
symptom known as "rosetting."

(B) Boron is not readily translocated from older
parts to the meristematic region, and the first
visual symptom is cessation of terminal bud growth,
followed shortly thereafter by death of the young
leaves. The youngest leaves become pale green,
losing more color at the base than at the tip.

(Mn) Like Fe, Mn is a relatively immobile element
and deficiency symptoms show up first in the
younger leaves. Deficiency of Mn results in inter-
veinal chlorosis, both on broad-leaf plants and
members of the grass family, but is less
conspicuous on the latter.








Molybdenum:









Copper:













Miscellaneous:


(Mo) Deficiencies have been reported for many
crops, including clover, alfalfa, grasses, tomato,
sweet potato, soybean, and other vegetables.
Symptoms of Mo deficiency differ with various
crops, but they are first observed as interveinal
chlorosis. Legumes usually turn pale yellow and
become stunted; symptoms characteristic of N
deficiency. These symptoms are consistent because
Mo is required by Rhizobia for N-fixation and by
non-legumes for NO3 reduction.

(Cu) Crops responding to Cu fertilization include
red beets, carrots, clover, corn, oats, and fruit
trees. Deficiency symptoms vary with different
crops. In corn, the youngest leaves become yellow
and stunted and as the deficiency becomes more
severe, the young leaves become pale and the older
ones die. In advanced stages, dead tissue appears
along the tips and the edges, of the leaves in a
pattern similar to K- deficiency. Small grains
deficient in Cu lose color in the younger leaves that
eventually break and the tips die. Leaves of many
vegetable crops lack turgor, develop a bluish-green
coat, become chlorotic and curl, and flower
production fails to occur.

Sodium, chloride, and silica have been shown to be
beneficial for some crops, but no definite deficiency
symptoms occur. Cobalt is reported to be beneficial
for legumes and some non-leguminous plants and is
essential for ruminant animals. Vanadium has been
reported as beneficial for green algae and N-fixing
bacteria.


It is often difficult to distinguish among deficiency symptoms in
the field if more than one element is inadequate. Confirmation of
deficiencies by visual observation is frequently difficult or impossible if
the deficiency is marginal. Also, disease and insect damage frequently
will resemble certain micronutrient deficiencies. Therefore, it is usually
necessary to employ supplementary techniques to refine or verify visual
observations.


Tissue Tests

Another method for identifying soil nutrient problems is to take
tissue tests. Important corollary factors that must be considered in
interpretation of tissue test results include the general appearance and
vigor of plants, level of other nutrients in plant, evidence of disease








and insect damage, soil moisture content, soil conditions such as poor
aeration or poor tilth, climatic conditions such as unseasonable cold or
heat, and time of day.
To take tissue tests, plant sap is extracted with reagents or by
pressure. Tests for N, P, K, Mg, and Mn are made with various
reagents giving semi-quantitative values interpreted as high, medium,
and low. The best part of the plant to use for testing is generally
that showing the greatest range as the nutrient goes from adequate to
deficient levels. The part of the plant to be used is specified in the
instructions for each commercial test kit. The parts recommended are
based on mobility principles as illustrated by the following examples.
As the supply of N decreases, the upper part of the plant, where
maximum utilization of plant nutrients is in progress, will first show a
low test for NO3. The reverse is true for P and K. Young leaves
should not be tested, but leaves from an area that is somewhere
between young and old, based on the area where deficiency first
occurred, should be selected.
In general, the most critical stage of growth for tissue testing is
at bloom time or from bloom to early fruiting. During this period
maximum nutrient utilization occurs and low nutrient levels are more
easily detected. In corn the leaf opposite and just below the uppermost
ear at silking stage is usually sampled. Thus, reconnaissance surveys
should closely coincide to the early reproductive stage if possible.
However, early diagnosis of deficiencies in the post-seeding stage
enables the application of fertilizer that results in increased yield the
same season the deficiency is detected. The time of day a sample is
collected influences NO3 levels in plants since NO3 usually accumulates
at night and is utilized during the day when carbohydrates are synthe-
sized. This results in higher NO3 levels in the morning than in the
afternoon if the supply is short. Therefore, tests should not be made
either early in the morning or late in the afternoon. Plant analyses are
based on the premise that the amount of an element in a plant is an
indication that supply of that nutrient is directly related to the avail-
ability in the soil. However, a deficiency of one element will limit
growth, and other elements may accumulate in the cell sap and show
high levels regardless of the supply. The apparent high levels may







actually be inadequate if the most limited nutrient is raised to an
adequate level. Periods of intense cold or heat, and conditions of poor
aeration may significantly alter the uptake level of different nutrients.


Paint and Spray Tests

Especially useful for diagnosing and confirming micronutrient
deficiencies are paint and spray tests. If a uniformly chlorotic plant is
found, 3 to 5 percent solutions of Fe, Mn, Zn, Cu, and a combination
of all can be applied to different leaves with a paint brush. Leaf color
changes occurring within a few days indicates deficiencies and
response. Solutions may be sprayed on whole plants in a field or an
area if a field is chlorotic.


Imbalances and Toxicity
An excess of one element can produce an imbalance in other
nutrients and reduce crop yields. For example, an excess of Mg can
produce a calcium deficiency. Micronutrients, such as excessive B, Zn,
Mo, and Cu, produce a toxicity. Toxicity and nutrient imbalances
produce somewhat different symptoms on different crops. Only the
most skilled diagnostician is able to identify these problems visually.
Usually plant analyses under laboratory conditions are necessary for
satisfactory resolution of these complex problems.


Chemical Soil Tests
Advantages of analyzing soil samples are that 1) precise
quantitative measures of available nutrients from thoroughly researched
extractants can be obtained, and 2) analytical results from representa-
tive samples taken before the crop is planted can be used as guidelines
for obtaining optimal yields. In some cases, sampling during the
cropping season at periods of peak nutrient demand may be advisable.
Certain nutrients on some soils may become limited during peak demand
periods, such as initiation and reproduction.


General Fertility Guidelines

General guidelines for interpreting available nutrient levels are
shown in Table 7.








Table 7. General fertility guidelines for some nutrients.


Very low Low Marginal Adequate High
Organic
Matter 1%
P 0-7 ppm 7-15 ppm 15 ppm
K 0-60 ppm 60-120 ppm 121-180 ppm > 180 ppm
Fe 0-2.5 ppm 2.6-4.5 ppm 4.5 ppm
Zn 0-.25 ppm .26-.50 ppm .51-1.0 ppm 1 ppm
Mn 0-1 ppm 1 ppm
Cu 0-.2 ppm 0.2 ppm


Plant Analyses

Plant analysis in the laboratory is more precise, and a greater
variety of analytical techniques can be used resulting in more quantita-
tive data than with tissue tests. These analyses can be used in
relation to more specialized problems such as determination of efficiency
of N-fertilizer usage.


Physical and Chemical Properties of Soil Root Zone

Portable equipment may be taken to the farmers' fields to study
root zone properties. Tools needed include shovels, soil sampling
tubes, a pocket knife, a bottle of 6N HC1, and a portable soil pH-test
kit. Pits should be dug in representative areas to expose the full root
zone depth. Systematic notes should be recorded for major horizons or
layers in relation to factors such as root proliferation, texture,
structure, compaction, lime content, salinity, pH, gypsum, and
aeration.
For a detailed analysis, penetrometer, infiltration, and four-probe
measurements may be required. The penetrometer can be used to
measure resistance to penetration in compact zone and hard-pan layers.
This will give a quantitative measure that can be related to observed
root penetration. Infiltrometers can be used to measure the relative
difference between water movement in different layers. This is usually
done with a double-ring infiltrometer. A vertical four-probe device can
be calibrated and used to obtain measurements of root zone soil salinity
(e.g., 15 cm intervals to 120 cm depth).








Subsoil Properties

Subsoil properties can be identified from visual observation of pits
or soil cores. Notes on water table level, textural changes, and lateral
permeability should be taken. Permeability measurements are usually
made by the auger-hole and piezometer methods. These measurements
are used to assess drainage feasibility and to calculate drain spacing.


Topography

If topographic maps are not available, measurements of elevation
and slope must be taken. Elevation affects the quality of the incident
solar radiation absorbed by the crop. Thus, information concerning the
general elevation of an irrigated area and its variations should be
obtained. Depressions and low-lying areas that may be more suscep-
tible to frost or cold air drainage should also be considered. Low-lying
terraces along rivers that may be more subject to flooding and a
fluctuating high water table should also be noted. Amount of sloping
land in the area should be obtained, as well as measurements of the
degree of sloping. Evidence of erosion indicating an improperly
designed irrigation system should be acknowledged. Very flat land with
little or no slope may represent drainage problems. Special precaution
must be made to note a "closed-basin area" in which no surface or
subsurface drainage occurs away from the irrigated area.


CLIMATE

Climate of an irrigated area generally controls the crop production
attained since it cannot be changed much by man. Climatic data,
therefore, are necessary to determine and evaluate many crop produc-
tion restraints including water supply, crops produced, crop water
requirements, incidence of insect pests and diseases, and availability of
soil nutrients.


CHECKLISTS

An example checklist is shown in Table 8 for reconnaissance of
crops and soils. For the Problem Diagnosis subphase, Table 9 provides
a checklist for studies of crops and soils.








Table 8. Checklists on reconnaissance methods for crops and cropping
patterns and soils.


*NOTE TO USER:


These checklists are to be used as a guide and are
not complete for every situation. Areas of
investigation may have to be added to meet project
requirements. Particularly in the reconnaissance
phase, utilization of existing data will save much
time. However, observations on the farms and
personal contact with farmers to verify the data
must be made by project personnel.


CROPS AND CROPPING PATTERNS


Crop inventory:


Crop stands:






Crop damage:









Potential yields:


Obtain existing information, including general
maps, from official agricultural statistical
agencies.
Obtain existing information, including possible
detailed field maps, from irrigation officials.
Obtain aerial photos used in soil surveys
showing field layout farms.
Gather information by interviewing selected
farmers.
Observe crops grown on-farm.
Other (specify)

Field observation: well-trained agronomist
can estimate plant population with considerable
accuracy.
Calculate plant population from seeding rate
and purity under various conditions.
Other (specify)

Obtain existing information from such sources
as plant protection officers or experiment
station personnel.
Make field observations at various times during
the cropping season to identify types of
damage occurring.
Interview farmers for general information on
damage factors.
Other (specify)

Obtain data on potential yields from local
experiment station. (Exercise judgment in
determining how closely optimum conditions
have been met).
Interview local "best farmers" for insight into
potential yields in the area.
Other (specify)








Actual yields:


Crop quality/
nutritional value:


Obtain field observations of harvest.
Interview local farmers.
Obtain agricultural statistics from government
agencies.
Other (specify)


Observe and evaluate qualitatively crops by
trained agronomists and nutrition specialists.
Place qualitative value on total calorie content
from generalized knowledge of average
carbohydrate, protein, and fat content.
Other (specify)


SOILS


Soil nutrient
supply:


Obtain existing data from
agencies.
Use visual observation of plants.
Take soil and tissue tests.
Conduct paint and spray tests.
Other (specify)


Root zone physical &
chemical properties:
Check root proliferation: depth and pattern
of root development. Should record changes
in rooting habit with textural changes or other
layer changes. Shallow restricted root zone is
evidence of a root-zone problem.
Determine soil texture. Moisture retention is
mainly related to texture.
Note soil structure type and degree of
development. Also, record evidence of
aggregate breakdown, surface crusting, and
cracking.
Study compaction. Evidence of compaction or
"plow sole" can usually be seen and confirmed
by resistance when pushing a soil sampling
tube into the soil.
Record lime content as low, moderate, or high
as judged from effervescence of CO2 when HC1
is dropped onto soil. Physically hardened
layers should be noted.
Obtain evidence of salt accumulation if present
at either the surface or in root zone.
Detrimental accumulations of salt can usually
be tasted with the tip of the tongue, whereas
lime and gypsum cannot.


agricultural





















Subsoil properties:


Topography:


Field-test pH. A field-test of pH of 9 or more
indicates either excessive Na or excessive
Mg. A lower pH, however, does not eliminate
either Na or Mg as a problem.
Examine gypsum layers within the root zone.
Thick gypsum layers may impede root
development because of infertility or physical
hardening, impede water movement, and may
lead to subsidence of land under irrigation.
Check aeration. Waterlogging and reducing
conditions result in a mottled soil color.
Other (specify)

Check water table level. Shallow water table
results in poor root aeration and acceleration
of salt accumulation in the root zone.
Note abrupt changes in soil texture from silt
or clay to sand or gravel. These changes
impede water penetration and can cause a
"perched water table."
Other (specify)

Measure elevation of fields.
Check amount of sloping land in area.
Measure degree of sloping in the area.
Other (specify)








Table 9. Checklists on detailed diagnostic methods for crops and
cropping patterns and soils.


CROPS AND CROPPING PATTERNS


Crop inventory:


Crop stands:


Crop damage:


Take aerial photographs to determine field
patterns and sizes.
Calculate acreages involved from average field
patterns and sizes.
Interview more farmers and at greater length
than before.
Other (specify)

Obtain field measurements. Stand counts in a
measured area at several places in the field
may be used to calculate a mean plant
population for the entire field.
Calculate germination percentage. Germination
percentages should be determined from seed
sold by dealers and seed held over from
previous seasons by farmers.
Take impurities tests. Determine amount and
kind of weed, other crop seed, and varietal
mixing in representative crop seed from the
irrigated area under investigation.
Investigate low germination seed. Signs of
excessive heat, excessive cracking, shattering
from freezing, interrupted germination, or
excessive shrinking from respiration during
storage will help determine the causes of low
germination.
Examine seedbed. Look for evidence of soil
crusting; excessively shallow or deep seeding;
or lack of moisture or excessive moisture.
These parameters may explain poor stands
when seed has a high germination rate.
Study time of seeding. Check time when the
seed was planted. Seeding when the soil
temperature is too hot or cold may cause low
germination and poor stands.
Investigate seed and seedling disease. Field
examination at emergence or post-emergence
may be necessary to detect stand loss from
seedling diseases.
Other (specify)

Take complete inventory of weeds, diseases,
insects, rodents and animals, weather
conditions, and herbicides in location under
examination.
Other (specify)








Potential yield:




Actual yield:





Crop quality/
nutritional value:












Soil nutrient
supply:


Cooperate with local farmer to observe fields
under carefully defined and controlled
conditions to determine the potential yields of
various crops.

Use spot field measurements in small sample
areas of local farmers' fields.
Interview farmers to determine amount of crop
sold, consumed by the family, and needed for
barter payments.


Take chemical analyses to determine specific
kinds and contents of sugar and starch in
carbohydrates, amino acids in protein, and
kinds of lipids in fat.
Analyze vitamin and mineral content.
Evaluate changes brought about by processing
and cooking.
Other (specify)


SOILS



Analyze soils for organic matter and nitrate,
lime content and pH, phosphorus, potassium,
sulfate, boron, iron, zinc, manganese, and
copper.
Do plant analyses.
Use field fertilizer trials.
Other (specify)


Root zone physical &
chemical properties:
Take soil samples. Characterize by saturated
paste extract, ammonium acetate extract, pH,
cation exchange capacity, calculation of SAR,
lime content, and gypsum content.
Take penetrometer measurements.
Make infiltration measurements.
Measure soil salinity with four-probe device.
Other (specify)


Subsoil properties:


Check lateral permeability in the fields.
Other (specify)








INTERDEPENDENCY OF PLANT ENVIRONMENT WITH FARM
MANAGEMENT PRACTICES

Providing optimal growth conditions for crop plants in order to
attain high levels of production are complex and sensitive processes
that are usually intricately related with management. In the Problem
Identification phase, identifying a deficiency of a particular growth
factor is usually only the initial step in identifying the exact cause or
causes of the problem. A particular growth factor deficiency or
inefficient utilization of the growth factor by plants can generally be
traced to management-related causes. The cause of the problem may
not be readily apparent, but in most cases the cause can be revealed
by studies of farm management and farm services in an irrigated area.
Most farmers can seldom, if ever, be accused of deliberate
mismanagement. Poor management is created most often by lack of
knowledge or specific information and unfavorable economic factors,
sometimes by social constraints, and quite often by factors beyond the
control of the farmer. Therefore, careful studies of the farm setting
and management practices are mandatory for identifying problem causes.
Guidelines for such studies are explained in Chapter III, "Farm
Management Practices."
The following hypothetical example illustrates how a general
fertility problem, such as N-deficiency, might be traced to management-
related causes. The general problem is presented and different specific
causes are listed in Table 10.


Case Study

Observations of plant growth by technicians in the field during a
reconnaissance survey of farms indicated a nitrogen (N) deficiency for
a given summer crop. This was confirmed by plant tissue tests. More
detailed studies of plant samples also showed the N-fertilizer that was
applied by the farmer was not used efficiently by the plant which had a
low N-recovery. Interviews of farmers within the area revealed that
N-fertilizer was not available on the local market at the time fertilizer
was normally applied due to a strike by transportation workers. After
some delay, the farmers planted the crop without the usual broadcasting
(throwing material by hand onto the ground surface) of fertilizer and










Table 10. Hypothetical case study of symptoms and causes of
nitrogen deficiency.



Fertility Problem

1. Nitrogen (N) deficiency
2. Low. N-recovery by plant

Visual Symptoms

1. Pale leaf color
2. Firing of lower plant leaves

Measurements of N-deficiency and N-recovery

1. Plant tissue tests
2. Plant sample analysis

Possible Cause or Causes of N-deficiency

1. Low inherent N-fertility
a. Low soil organic matter content
b. Low rate of organic-N mineralization
c. Failure to incorporate crop residues in soil
d. Continuous deposition of silt from irrigation water

2. Low N-recovery
a. Ammonia volatilization of broadcast ammonium-N or urea-N,
fertilizer not mixed into soil quickly
b. Leaching of nitrate-N below root zone by excessive irrigation
conditions
c. Nitrate reduction and gaseous-N escape under reducing
conditions
d. Ammonium-N fixation by mica and vermiculite clays
e. Deficiency of other nutrients such as P

3. Application of N less than that required to produce a given
crop yield
a. Fertilizer too costly
b. Fertilizer not available on open market
c. Fertilizer not distributed uniformly over field
d. Inaccurate fertilizer recommendation

4. Fertilizer not applied at recommended time
a. Lack of information about timing
b. Fertilizer not available when needed
c. Insufficient labor or machinery at critical time
d. Inaccurate fertilizer recommendation








working it into the soil before planting. The strike was settled and
farmers bought fertilizer after the crop had emerged and broadcast the
fertilizer on the soil surface but could not incorporate it into the soil.
The fertilizer (urea) sat in the hot sun on the ground surface several
days before irrigation water was first applied. Farmers observed that
the crop did not grow normally and since an above-normal supply of
water was available at that particular time, extra heavy irrigations were
applied with the hope that extra water would improve crop growth.
Crop yields for this particular season were substantially lower than the
previous average.
In this case study, no one particular cause can be cited for the
N-deficiency. It is highly probable that volatilization losses of ammonia
from the urea were high because the urea sat in the hot sun for
several days. It is also probable that further losses of N below the
crop root zone resulted from overirrigation. Some loss in yield
probably resulted from the delay in planting the crop as well. Thus,
part of the management problem was due to circumstances beyond the
control of the farmer. The failure of the farmers' attempt to compen-
sate by overirrigating was due to lack of knowledge concerning the
leaching process.








CHAPTER IV


FARM MANAGEMENT PRACTICES


Good farm management practices are essential to increased
agricultural production. In order to identify problems that impede
optimum production, the Problem Identification phase must include a
close examination of the farm management practices in the irrigated area
under study. As with each phase of this process, examining the
problems with farmers is important to success. This chapter will focus
on inventories of management practices, cropping patterns, and
resources; farm budgets; the farmers' decision-making environment; and
the interdependency of the management practices with the farmers'
community (Figure 5).
There is a natural overlap between many aspects of the plant
environment and farm management practices. This is true for the
agronomist and agricultural engineer who are concerned with soil and
water management practices employed by farmers on cultivated fields.
Much of this information is used by the social scientists. The farm
management economist is concerned with cooperative costs and benefits
of alternative management practices. Both the economist and sociologist
or anthropologist is interested in the decision-making environment and
its impact on farm management practices.


IRRIGATION PRACTICES

The specific methods of irrigation for various types of crops need
to be identified and evaluated for effectiveness. Field application
evaluations will help determine whether the farmer is overirrigating or
underirrigating in relationship to crop demands and water required to
maintain adequate control over salinity problems. These evaluations
should supply data on the desired volume of water distributed uniformly
over fields, erosion and salinity control, drainage problems, and the
economic feasibility of the methods used. Important variables in these
irrigation evaluations include water supply rate, field geometry (length
and width), slope, infiltration rates, surface roughness, channel slope,












Canal

Inventory of Practices
-Field descriptions
-Seedbase preparation
-Cropping patterns
-Purchased inputs
-fertilizer
-seed
-pesticides
-herbicides
-machinery
-Irrigation
-Harvest
-Storage choe-


I Cropping Patterns |
Cropping intensities
Crop rotation
Crop mix
Polyculture


-Land
-Labor
-Physical capital
-Commercial inputs
-Water inputs
-Output'


decisionn maK1ng
/ I Environment
-Prices
-Tenure
-Farm practices
-Information
-Markets
-Risk taking
Drainage ChanTels
cr ------- T i


Idealized sketch of a farm irrigation system and farm management practices.


Figure 5.








and management decisions related to the methods. Three basic
questions that need answering are: How does the farmer irrigate?
When does the farmer irrigate? How much water does the farmer apply
to various crops? The major task is to evaluate irrigation practices in
relationship to costs of alternative methods.


Farm Water Use Efficiency

Farm investigations constitute the largest proportion of work
involved in the evaluation of an irrigated area. The primary component
of this investigation is the farm efficiency studies which include
evapotranspiration, infiltration, tailwater, irrigation method analysis,
and vegetative land use mapping.
The amount of water diverted is also very critical in establishing
the water-salt budgets for a farm or a field. All of this water must be
measured and accounted for, and it is allocated to any one of three
main categories. The surface hydrology categories are
(a) evapotranspiration, (b) infiltration and (c) tailwater runoff
(Figure 6). In areas with a high water table, there can be a
substantial amount of water that moves upward via capillary action from
the water table and is used by the plants. This capillary water will
usually contribute significantly to soil salination problems. The
subsurface hydrology categories are head ditch seepage and deep
percolation losses. The variables that must be considered in an
on-farm irrigation investigation are schematically illustrated in Figure 7.
Many of the parameters such as drainage discharges, watercourse
diversions, water quality, and precipitation can be measured directly.
Others must be investigated indirectly. These indirect measurements of
parameters are related mostly to groundwater movement and soil
hydraulic characteristics and can be monitored using techniques such as
piezometers, wells, and soil sample analyses.
Because so many of the parameters in the water and salt budgets
cannot be evaluated directly on a large scale, peripheral investigations
are usually made in which a portion of the area is examined in detail.
Such investigations include farm efficiency studies that indicate the
relative proportion of evapotranspiration, deep percolation, and soil
moisture storage; vegetative land use mapping of the entire irrigated



















Structure


Field Evaluation
) of Soil Moisture


_- --- ( Hydraulic Elevation of
S ---.-- Irrigation Pprformance Flo Measurcmcnt
x-T SIr ucture
Weather -Tu t r. Scu
Station- T
/ ,- *-,, ....
/ ----- ....... .. 'Tailwater
Deep Percolation Runoff
Losses

Note: Schematic illustrates furrow irrigation. Border irrigation would be similar.
Basin irrigation would not have tailwater runoff.


Figure 6. Schematic of instrumentation required for on-farm hydrology investigations.

















Transpiration


Infiltration


I


Root Zone
Extraction
i 1 I


SDeep
Percolation


Upward Flow by Capillarity
4 A 4 4 4


Water Table


Groundwater Flow


apillary Fringe
of Water Table


Figure 7. Schematic of the hydrologic variables to be considered
in an on-farm subsystem investigation.


I I L--~








area so that the total consumption of water for the area can be
calculated; and other studies pertaining to specific conditions of water
and salt movement. There is no substitute for good field data
collection. The United States Geological Survey (1968 to 1976) has
published 34 manuals on techniques used for water resource data
collection, many of which are very useful for irrigation studies.
Four types of basic data are required for on-farm water use
investigations. These are crop parameters, soil parameters, water
quality information, and climatic data such as evapotranspiration and
precipitation data.
Crop parameters are important to many of the irrigation method
decisions and the plant sensitivity and ionic toxicity response to
salinity, growth rates, and evapotranspiration demands. Crop
responses to salinity are discussed by Bernstein and Hayward (1957),
Bernstein et al. (1954), Black (1968), Maas and Hoffman (1977),
Robinson (1971), and others.
Soil parameters considered as basic data include field capacity,
permanent wilting point, and bulk density for each soil layer with
depth. Since field soil-moisture sampling procedures are gravimetric,
the bulk density is needed to relate gravimetric to volumetric moisture
content which is used in most analytical procedures. An attempt should
be made to obtain several samples from numerous locations to
approximate the average conditions of the field (Warrick, 1977; Karmeli
et al., 1978). Basic soil chemistry reactions, electrical conductivity and
ionic content of the soil solution should also be determined. Black et
al. (1965), Food and Agricultural Organization of the United Nations
(1975), Quirk (1971), Richards (1954), Chapman (1966), and others
describe the soil-chemistry-plant relationships and procedures for data
collection and analysis.
Quality of the incoming water can greatly influence management
and operation of an irrigation system. If the water is of poor quality,
it can limit many of the alternatives for pollution control. Ayers
(1976), Ayers and Westcot (1976), Christiansen et al. (1976), Kemp
(1971), Kovda et al. (1973), Wilcox and Durum (1967), and others
present information regarding water quality in irrigated agriculture.








Crop Water Use

Evapotranspiration (ET) or consumptive use (CU) is the sum of
the amount of water evaporated from the soil surface and the amount of
water transpired by the crop. The primary factor controlling ET is the
thermal energy of solar radiation reaching the surface of the earth.
However, solar radiation, air and soil temperature, humidity, vapor
pressure, wind velocity, and specific crop and variety are all inter-
related factors in the ET process. Potential evapotranspiration (ETp)
is a convenient weather index or reference point by which weather-
related evaporative conditions can be related to specific crop-water
needs. Potential ET has been measured as open-pan evaporation and
calculated by various formulas that include varying amounts of
climatological data with and without corrections for altitude and latitude.
The Jensen-Haise method uses calculated ETp from solar radiation for
alfalfa as a reference crop. Actual evapotranspiration (ETa) is usually
less than potential evapotranspiration because of moisture stress
experienced by the plant prior to irrigation, unless sufficient irrigation
water is applied frequently.
Some data on ET may already exist at universities, experiment
stations, or governmental agencies. Data for crops in other irrigated
areas with similar climatic conditions transferred directly to local
settings may be accurate enough for some purposes. In the absence of
ET data, calculations can be made from existing weather data for the
local irrigated area using crop coefficients developed in other areas.
Determination of ETa at the peak, with maximum rates occurring
near the onset of flowering and minimum rates occurring near the
germination and late maturation stages, is necessary to determine the
proper time for irrigation. Probably the most accurate way to measure
ETa is from lysimeters; however, gravimetric moisture or neutron probe
measurements taken before and after irrigation under field conditions
where no water table exists near the crop root zone can be
satisfactory. Weighing lysimeters surrounded by the same crop can
furnish daily ETa data more easily than soil moisture sampling.
Considerable care must be taken to duplicate conditions of the natural
environment or else results will not duplicate those found in the field.








Inflow-outflow studies along with accurate water table level
measurements can furnish sufficiently accurate average data for large
areas. Crop water-use coefficients (k or K) can be developed from ETa
data at the various stages of crop growth for particular ETp data.


Open-Pan Evaporation

Open-pan evaporation data can be used as a direct measure or
index of ETp. Daily data can be summarized for various growth
periods by months or for different seasons.


Other Devices for Measurement of Evaporation

Piche tubes and atmometers have been used in many places but
have not achieved popularity in the United States. Use of these
devices would necessitate the development and use of some different
crop coefficients than for open-pan evaporation.


Calculation from Weather Observation Data

Potential evaporation has been calculated or estimated by many
different formulas varying in complexity. The following formulas are
listed in a decreasing order of the amount of weather data needed:
Penman, Christiansen, Hargreaves, Jensen-Haise, Blaney-Criddle,
Thornewaite, and Lowry-Johnson. The Penman and Thornewaite
formulas are best adapted to humid, well-vegetated areas.
Tanner (1967) and the World Meteorological Organization (1966)
provide an excellent review of the procedures and methodologies used
for the measurement of potential evapotranspiration in, the field.
Measurement of evapotranspiration should include the means for the
actual measurement of consumptive use and a complete weather station
to measure air temperature (including maximum and minimum daily
temperatures), dew point temperature, relative humidity, precipitation,
wind run, solar and net radiation, and evaporation (Class A pan).
Doorenbos (1976) presents an excellent discussion on the establishment
and operation of a weather station and the calibration of empirical
evapotranspiration indices to actual evapotranspiration measurements.
The World Meteorological Organization (1970 and 1971) presented much
information on the collection and analyses of hydrometeorological data.








Lysimeters

Probably the most accurate measurement of evapotranspiration is
obtained by the use of lysimeters. A lysimeter is a device that is
hydrologically isolated from the surrounding soil. This device contains
a known volume of soil, is usually planted to the crop under study, and
has some means to directly measure the consumptive use of water.
Lysimeters must be representative of the surrounding conditions and
the soil types if they are to provide useful evapotranspiration
measurements. Lysimetry establishes a datum for evapotranspiration
calculations because it is the only method of measuring evapotrans-
piration where the investigator has complete knowledge of all the terms
of the water balance equation. Harrold (1966) presents a comprehensive
review of the use of lysimeters for measuring evapotranspiration.
Two types of lysimeters, which have worked quite well for
calibration purposes, are the constant water table and the hydraulic
weighing lysimeters. The constant water table lysimeters (Figure 8)
are usually planted to grass or other crops with shallow root systems.
On the other hand, the hydraulic weighing lysimeters (Figure 9) are
usually planted to deeper rooted crops, such as alfalfa or corn.


Irrigation Timing
Irrigation water must be applied frequently enough so the crop is
not subjected to a great degree of soil moisture stress in order to
achieve full production. Proper timing depends on the water require-
ment of the particular crop, the stage of crop growth, the moisture
storage capacity of the soil, and availability of water to the irrigator.
Maintaining readily available soil water is essential if crops are to
achieve satisfactory growth.


Field Observations

Determination of soil moisture content can be done by the Touch
and Feel method. Soil that will not form a ball is an indication of
inadequate soil moisture. A dark green color and signs of wilting by
the crop indicates that soil moisture is limited. However, these
symptoms may be difficult to distinguish from the symptoms of salinity.







































Valve


Water Stage

Recorder


servoir


SSoi2l 4 Tubing








Welded Aluminum Lysimeter

Tank Im x Im x 0.46m


Figure 8. Schematic of constant water-table lysimeter.


-..:


IL;




~p.. ,
I
""
' '
.r;~





































Dummy Lysimeter
for Temperature Correction


Nylon Reinforced
Butyl Rubber Tubing


Figure 9. Schematic of the construction of a hydraulic weighing lysimeter.








Calculations of ETp and ETa frcm Ei: .. Data

Estimates of soil mroisture-holdinlg capacity along with ETa estimates
for a specific time period give a reasonably good indication of the rate
of crop-water use. If available water stored in the root zone at each
irrigation is less than estimated ETa for that period, calculations
indicate that irrigation is applied too infrequently.


Field Measurements

Fundamental characterizations for evaluating proper irrigation
timing is the determination of field capacity, wilting point, and amount
of available soil water stored between these two values for a given soil.
Usually the best crop growth will be obtained if soil moisture does not
fall below 50 percent of the available supply, generally called the
"readily available" supply. In terms of soil moisture stress, the readily
available moisture usually falls into the range of less than 1-2 bars
tension.


Tensiometers, Gypsum Blocks, or Fiberglass Blocks

Tensiometers are well-adapted for sandy soils. The range in their
measurement is from 0-1 bar tension. The range in gypsum and
fiberglass blocks is from 1-15 bars tension and these are best adapted to
medium-to-fine-textured soils. The above devices can be used as a
check to see if irrigation frequency is satisfactory or as a guide to
application time.


Gravimetric and Neutron Probe Moisture Measurements

Either gravimetric soil moisture samples or neutron probe
measurements can be used to evaluate the acceptability of the usual
timing of irrigation. These measurements can also be used to develop
guidelines for the best irrigation timing practices. Measurements of
this type are usually fundamental for any "water budget" or "water
balance" studies, which are defined in the next chapter. Direct
measurement of soil moisture is potentially the most accurate method for
evaluating irrigation timing, especially if groundwater is utilized by
plant roots.








Irrigation Timing as a Function of ET Estimates

Estimates of ET from open-pan measurements and/or climatic data
entail somewhat less work than gravimetric moisture sampling or neutron
probe measurements since they are independently determined. If it is
possible to change the time of irrigation, then it can be adjusted to fit
climatic changes.


CROPPING PRACTICES


Cropping Patterns

Cropping patterns, as shown in Figure 10, refer to the cropping
intensities and crop rotations including fallow, crop mixes, polyculture,
and relay cropping. The first step is to determine the definition of
cropping intensity being used in the region or country. Usually there
is one accepted definition used by the agricultural census or the
Department of Agriculture in a country. Some definitions and examples
of cropping intensities are given in Table 11.


Crop Rotation
Investigation of crop rotations ascertains the actual sequences of
crops grown on different fields. Also, the use of fallow for each field
over time is recorded.


Crop Mixes

The purpose of a crop mix study is to check the types of crops
cultivated for individual farms and a large area. For example, is the
farm primarily a wheat-cotton farm, a wheat-fodder farm, a vegetable
farm, or one with a variety of crops?


Polyculture

Polyculture is the degree of intercropping of several crops in a
single irrigation basin or field, and should be determined. In many
parts of the world there are sound reasons for polyculture. Farmers
with small acreages report that such practices exist for several reasons
such as there is a more even distribution of income over the year, a
lack of sufficient land to feed family and animals, insurance against one





66
WATER MANAGEMENT RESEARCH PROJECT

WATERCOURSE SURVEY SAMPLE VILLAGE= NO. 103

DISTRICT LAHORE

WATERCOURSE COMMAND I


GENERAL FEATURES


MOGHA NO. I -_
W




.]

.-.- w t*


LEGEND
W- WHEAT
B- BERSEEM
F-FALLOW
Sc-SUGAR CANE
Os-OIL SEED Scale= 0 220 440660
Br-BARREN
Fd-FODDER
G-GARDEN
S- -DISTRIBUTARY
S- MINOR
S- HOUSE ORDER


-WATERCOURSE
M -NAKKAS
JHALAR
0/ TUBEWELL/MOGHA


: U::N:: CULT BARREN
ACRE BOUNDARY
AREA BOUNDARY


Figure 10. Example of agricultural land use mapping.










Table 11. Definitions of cropping intensity.


Definition 1:


Total area in acres or hectares
cropped for two major seasons
Total area of cultivated acreage
or hectares


x 100


Example: A farm has 5 acres and two seasons (two
crops per year can be harvested). If the farmer
cultivates the five acres each season, then a total of
10 acres is cultivated each year and the cropping
intensity is

10/5 x 100 = 200%


Definition 2:


Total area in acres or hectares
cropped for more than two major
crops
Total area of cultivated acreage
or hectares


x 100


Example: If a farm having 5 acres can grow three crops
in a year and 5 acres are cultivated one season, 3 acres
another season, and 4 acres for another season then the
cropping intensity is

12/5 x 100 = 240%


Definition 3:


Total area in crops harvested in
two or more seasons
Total area cultivated


Example: A farm has 20 cultivated acres but 10 acres
are in perennial sugar cane harvested once a year and
10 acres in other crops for 2 seasons per year, the
cropping intensity would be

30/20 x 100 = 150%*

The 10 acres of sugar cane are counted as 10 acres because they are
harvested on a yearly basis (which would also be true for tree crops).
The other 10 acres produces 2 crops per year, so it is counted as
20 acres in the numerator.


x 100








crop failing, an improved crop cover, better utilization of water and
fertilizer inputs, symbiotic (nitrogen fixation) relationships of some
crops, insect protection, along with other advantages. However, little
experimental work has. been completed related to this widespread
practice on many farms around the world.


FARM BUDGETS

Farm Management Inventory

It is necessary to collect data from farmers about their actual
management practices (Table 12). Checklists are provided in Tables 13
and 14 for evaluating farm management practices. Data obtained from a
representative sample of farmers can help program staff answer many
questions about farm management.


Resource Inventory

In addition to technical information about actual farm practices, it
is necessary to gather information about resources available to the
farmers and the values of these resources; in production. Preparation
of budgets require price information and inventories. When price
information is complete, detailed farm budgets can be constructed for
use in analyzing the farmer's production choices and the value of his
resources.
Farms should be separated into homogeneous groups with respect
to their availability of resources and their productivity. For example,
farm size, tenure, and location may be adequate indices by which to
categorize farms. Thus, one category might be "small, low-land,
tenant-operated farms." The area map: mentioned earlier should be
useful to determine the .categories. Each category is then used to
compute an average or representative farm budget. As part of the
detailed diagnosis, a sample of land, physical labor, capital, animals,
water, and outputs should be made.


Land

Soil types and productivity, accessibility to markets for products
and inputs, size and shape of fields, size of holdings, access to water,
ownership and tenure arrangements, and markets and prices should be









Table 12. Format for inventories of actual practices for


A checklist in a formulated systematic approach for
and preserving management data is as follows:


obtaining


1. Name of farmer Date
2. Legal description of farm
3. Field designation
4. Field size
5. Preceding crop
6. Preceding fertilizer application
a. Amount of N, P, K, micronutrients applied
b. Manure
7. Present crop
8. Seedbed preparation
a. Type or types of tillage operation
1. Number of times and sequence
2. Type of power (animal, machine, man)
3. Desired seedbed condition (firm, mellow)
4. Planting system and method of planting
b. Time and labor required
9. Number of irrigations applied during land preparation
10. Fertilizer applied
a. Amount (N, P, K, micronutrients)
b. Method of application (broadcast, banded, split)
c. Number, type, and time of tillage operation to incorporate
fertilizer into soil
d. Commercial fertilizer cost
11. Seed
a. Source
b. Seeding date or dates
c. Purity (weed and other crop free)
d. Opinion of quality
e. Amount of seed planted (calculate seeding rate)
f. Cost
g. Method of planting
h. Seeding depth
i. Condition of seedbed (firm, mellow, moist, dry)
j. Type of power (man, animal, machine)
k. Time and labor required for seeding
1. Cost of custom work
12. Weed eradication
a. Preplant spray; material
b. Mechanical cultivation; man, animal
1. Date, number of times
2. Time and labor required for weeding
3. Cost of custom work


major crops.









Table 12. (continued)

13. Irrigation
a. Method of irrigation
b. Dates and number of times
c. Irrigation intervals
d. How much applied each time
1. Amount. of water received
2. Length of time on field
3. Amount of runoff (calculate field efficiency)
e. Labor required
14. Insect problem if noticed
a. Amount, type, and number of sprays
b. Cost of sprays
c. Time and labor involved
15. Disease problems if noticed
16. Other damage to crop
a. Farm animal, rodent or other, wind
17. Harvest operation
a. Date (period) of harvest
b. Method of harvest
1. Power source
c. Time and labor required
18. Yields
19. Storage facilities
a. Capacity
b. Amount stored
20. Cropping patterns
a. Cash crops
1. Number, sequence, and time and duration during
year
b. Subsistence crops
1. Number, sequence, and time and duration during
year
c. Crops grown together (crop mixes)
d. Intercropping practices (polyculture)








Table 13. Checklists on reconnaissance inventory for farm management
practices.


Cropping patterns:


Consult available data
Discuss with farmers and those who work
directly with farmers
Make direct field observations where possible
Other (specify)


Irrigation practices:
Consult available data from research stations,
etc. as to comparative benefits of various
practices used
Field visits to observe the alternative practices
used
Discussions with farmers and extension
personnel of comparative benefits of alternative
methods
Other (specify)

Resource inventory/
farm budgets: Consult available data: census, agriculture
department, agricultural studies, anthropolog-
ical studies, marketing board, ministry of
trade, labor data
Check existing data for farm size, tenure
system, water rights, capital availability,
pricing policies, government policies
Determine government policies on agriculture
commodities, quotas, prices, and distribution
of fertilizer
Check with agriculture extension agents for
existing data and to see if government policies
are effective
Other (specify)


Decision-making:


Crop varieties:


Determine degree of fluctuation in prices of
commerical inputs and crops. Comy ute
statistical variance, range, and use a sca-ter
diagram to detect special patterns in the data
Determine role of government control in crop
prices and input prices
Check dependability of marketing services
Investigate land tenure system, check security
of system from govern nent officials, legal
documents, studies, and extension agents
Other (specify)

Obtain available data from agricultural officials
and available research
Gain information from farmers and extension
workers









_ Compose estimates f i' e .-ul' from leading
and average farmers of variCus varieties of
given crops
Other ('.,i y)


Seedbed preparation:
Consult available information frnm agricultural
officials, and research and extension
specialists
Make preliminary field observations of farms
and discuss with farmers
Other (specify)

Planting/sowing dates:
Consult available data about costs and benefits
of optimum versus nonoptimum dates for
selected crops
Discuss with farmers their views of optimum
versus nonoptimum dates and perceived costs
Other (specify)

Seed source, quality
and seed rates: Consult available data on costs of seed from
various sources, benefits of using seed of a
known quality, and cost-benefits of optimum
seed rates for selected cror;s
Discuss with farmers ind extension workers
the cost of seed, the availability of quality
seed, and the value of certain rates of seed
per hectare or acre for selected crops
Other (specify)_

Fertilizer cost,
availability, use,
and methods of
application: Establish from available data the actual cost to
various farms for fertilizer, degree of
availability of fertilizer, the costs, benefits of
various levels of use, and costs and benefits
of various methods of ::,li.:.l'.in
Discuss with farmers and extension workers
their perceptions of the questions above
Other (specify)

Weed and insect control
methods: Establish from available data the costs and
benefits of various control methods
Discuss with insecticide agency staff and
researchers
Make initial field observations and discuss with
farmers and extension workers to determine
their perceptions of costs and benefits and the
degree of control that should be used
Other (specify)









ge: Obtain available data from research stations
and other organizations
Discuss with farmers and extension workers
and estimate the losses in production to all
farms due to crop damage
Other (specify)

:ions: Consult research station personnel and farm
machinery companies about benefits of
alternative methods of all tillage operations
Observe in the field what different operations
are used with what types of implements and
machinery
Discuss with farmers and extension workers
alternative costs and benefits of various
methods
Other (specify)

Jt operations: Consult available data to determine the
benefits in terms of actual yields of various
methods
Observe operations in the field and join
farmers' and extension workers' views of the
losses in crop output of various types of
harvest operations
Other (specify)


Storage facilities:











Market facilities:







Credit facilities:


Consult available data as to crop losses of
various storage methods. Document the types
of facilities from farm level to market centers
to national storage schemes
Discuss with market personnel the relative
benefits of various storage systems
Observe various storage systems from farm to
market center
Discuss with farmers losses from rodents,
mold, temperature, insects; and various
storage methods for major crops
Other (specify)

Consult available data from government offices
and marketing centers
Document modes of farm to market transporta-
tion and costs of each
Discuss with farmers the costs of marketing
farm products, including costs of middlemen,
transportation, and taxes
Other (specify)

Consult available data about sources of credit,
availability, use, and types and terms of
credit from credit institutions
Discuss with those who work directly with
farmers the questions above
Other (specify)








Table 14. Checklists on detailed diagnostic methods for farm
management practices.


Cropping patterns:


Irrigation practices:


Conduct crop survey and enter on map of
each field and season
Interview farmers using a grid system
designed for the units used (acres, hectares,
etc.). Data collector should verify reports by
checking,, the field individually for certain
crops.
Take aerial surveys if possible to do with
adequate detail and at proper time.
Other (specify)


Conduct field surveys to document the various
practices used and reasons why
Utilize. data from irrigation engineers to
document the actual losses of water and costs
of that water
Utilize data from engineers and agronomists to
document the influence of the application of too
much and too little water, and quality of water
on yields
Utilize data from engineers and agronomists to
estimate costs and benefits of various methods
of improved return flow of water.
Other (specify)


Resource inventory/
farm budgets: ___Conduct a sample survey to check land,
labor, capital, animals, water inventory, and
outputs
Other (specify)


Decsiop n-makin g


Crop varieties:


Determine prices and yields from direct
observation.
Observe terms of tenancy to verify or modify
information already obtained.
Observe farmers when they are planting,
irrigating, cultivating, and caring for their
crops.
Note how farmers adjust to problems of
uncertainty. Ask questions such as: "What
recourse do farmers have if they lose most of
their major crop? Is credit or support easily
available through the family? What food
reserves do the farmers maintain? What
minimum risk crops do they plant? What
is the amount of farmer's savings .(very
difficult tp determine)?
Other (specify)

Document the ; crop varieties along with
cropping patterns on field maps used by
farmers.








Crop varieties:


Document the crop varieties along with
cropping patterns on field maps used by
farmers.
Analyze the benefits in yields attributed to
varietal differences from on-farm data and data
at research stations.
Other (specify)


Seedbed preparation:
Conduct farm level surveys to document the
benefits and costs of various methods in terms
of yields and net farm income.
Other (specify)


Planting/sowing
dates:


Conduct field surveys with farmers and
acquire data from experiment stations to
analyze the reductions in yields resulting from
variations in sowing and planting dates for
major crops.
Determine if the range of sowing/planting
dates for various crops provide adequate
margin for farmers in terms of field
operations.
Other (specify)


Seed source, quality,
and seed rates: Conduct farmer interviews to determine source
of seed, availability, and quality of seed.
Obtain data from experiment stations about
seed quality and variations in yields resulting
from various levels of seed rates.
Establish the economic levels for various seed
rates in relationship to yields.
Other (specify)


Fertilizer costs,
availability, use
and methods of
application:


Conduct farmer survey to determine the costs
of fertilizer, availability at time needed, credit
availability, rates applied, and methods of
application.
Compose recommended levels of fertilizer and
methods of application for selected crops from
research stations and farmers' practices.
Compare project field data with that of
fertilizer companies.
Ascertain the economics of fertilizer use by
farmers
Other (specify)








Analyze the benefits in yields attributed to
varietal differences from on-farm data and data
at research stations.
Other (specify)


Seedbed preparation:
Conduct farm level surveys to document the
benefits and costs of various methods in terms
of yields and net farm income.
Other (specify)


Planting/sowing
dates:


Conduct field surveys with farmers and
acquire data from experiment stations to
analyze the reductions in yields resulting from
variations in sowing and planting dates for
major crops.
Determine if the range of sowing/planting
dates for various crops provide adequate
margin for farmers in terms of field
operations.
Other (specify)


Seed source, quality,
and seed rates: Conduct farmer interviews to determine source
of seed, availability, and quality of seed.
Obtain data from experiment stations about
seed quality and variations in yields resulting
from various levels of seed rates.
Establish the economic levels for various seed
rates in relationship to yields.
Other (specify)


Fertilizer costs,
availability, use
and methods of
application:


Weed and insect
control methods:


Conduct farmer survey to determine the costs
of fertilizer, availability at time needed, credit
availability, rates applied, and methods of
application.
Compose recommended levels of fertilizer and
methods of application for selected crops from
research stations and farmers' practices.
Compare project field data with that of
fertilizer companies.
Ascertain the economics of fertilizer use by
farmers
Other (specify)


Conduct field studies to determine actual
losses in crop yields due to losses from weeds
and insects.
Establish the economics of improved methods
versus farmers' methods.
Other (specify)









Other crop damage: Conduct field surveys to determine from
farmers actual cost of losses from animal,
natural, and human sources
Other (specify)


Tillage operations:


Harvest operations:


Storage facilities:


Market facilities:






Credit facilities:


Conduct field surveys to determine the capital
and labor costs of major tillage operations.
Determine from field surveys the benefits of
timely operations.
Determine the recurring costs involved from
purchased farm machinery and animal power.
Other (specify)

Document in field surveys the costs of all
operations and the value of timeliness in
operations.
Compare the costs and benefits provided by
equipment salesmen and farmer users.
Include in field studies the seasonal availability
and costs of labor
Other (specify)

Obtain data at the farm level about estimated
losses of crops in farm level storage
Obtain data from market centers and other
storage centers as to losses in storage and
calculate a total loss due to inadequate storage
facilities
Compare the costs and benefits of alternative
types of storage facilities and practices.
Other (specify)

Conduct farm level and market center surveys
to determine costs of transportation,
middlemen, and levies to the farmer.
_ Compare costs of various types of marketing
practices in which farmers are involved.
Other (specify)

Conduct field surveys to document source of
credit, type of credit, and costs of both
institutional and noninstitutional credit to the
farmer. Also, ascertain credit availability to
all classes of farmers.
Obtain information on credit availability and
terms of credit from both institutional and
noninstitutional sources.
Estimate the need for productive versus
consumptive credit needs for all classes of
farmers.
Other (specify)





78


included in the resource survey. A map is also useful to help
summarize all of this data and for suggesting representative farm
groups.


SLabor

Information should be collected on age, sex, health, number, and
education of family laborers. Also, it is important to know the tasks
performed by various:family, members and the availability of hired labor.
It is necessary to know the terms of hiring, the calendar availability of
off-farm work for laborers, and the wages to be paid.


Capital

Several questions: should be answered such as What are the
financial sources? Is it the farmers own savings or credit? If it is
credit, where was it obtained? Was it obtained from family, a money
lender, farmers,' a cooperative, a bank, the government? How much
does each farmer pay and under what: terms? What is the interest rate,
repayment schedule, and security?


Animals

An inventory of all animals, either raised for food or work should
be assembled. The animals' condition,: consumption requirements, market
value, labor required to keep them, and susceptibility to disease should
be noted.


Water Inventory

The availability of water at specific times, and other inputs
required to use it, including labor, machinery, and animal inputs
should be checked.


Outputs

Each crop should be inventoried according to its yield, its
requirements for specific timing of inputs, the cash costs of inputs,
and the prices on outputs.









Decision-Making Environment

Individual farmers do not allocate their resources independently of
their neighbors; rather, they are part of a complex web of obligations
connecting them with their neighbors and relatives. Farmers also
depend on average or normal returns such as those derived in the
representative farm budgets. The farmers are subject to extreme
variations in yields resulting from causes beyond their control such as
rainfall, disease, pests, sickness, market changes, and political
changes. Both competition between farms and variations related to
prices and other variables influence the individual farmer's decision-
making framework. Therefore, these factors need to be carefully
considered to understand basic causes of farm production problems.


Interdependency with Farmer's Community

A thorough study of farm management practices along with data on
crop potentials allows investigators to construct: (a) representative
farm budgets reflecting what farmers actually do, and (b) alternative
budgets reflecting what they could do, either with existing resources or
added factors. However, the farmer's real choices are strongly condi-
tioned by factors that are difficult for researchers to comprehend, let
alone quantify. These include uncertainty and obligations with
neighbors and relatives and the farmer's village environment as a
whole, which is the topic of Chapter VI.


INTERDEPENDENCY OF FARM MANAGEMENT PRACTICES WITH WATER
SUPPLY AND REMOVAL SUBSYSTEMS

As a means to show how farm management practices are closely
related to the water supply and removal subsystem, a hypothetical case
is utilized. It is assumed that crop stands on a farm are very poor
and limiting production. The agronomist investigates and discovers that
in both leaf tissue tests and analysis of soil samples there is a definite
nitrogen deficiency. The farmer reports, however, that he applied the
recommended rates of nitrogen. In turn, the hydrologist locates a high
water table resulting from poor drainage. Later, from measurements of
water losses from poorly maintained field channels and overirrigation, it
was found that irrigation efficiencies are only 25-30 percent. Also, it






was discovered that 40-50 'percent of the nitrates applied were leached
through the soil profile to groundwater. Further interviews with the
farmer revealed that he applied what water he could every week when
water was allotted on a fixed rotation system. It was learned that the
farmer applied all the water he could to his fields because of (a) lack
of knowledge of the appropriate amount to apply, and (b) concern that
canal supplies might not be regular.
In such a case, the investigator must be careful not to confuse
symptoms of problems with causes. Also, the investigator must learn to
search for multiple causes. For example, if the problem is defined as
poor crop stands, nitrate leaching and poor drainage are only
symptoms. The causes of the problem may be overirrigation resulting
from both lack of knowledge and a rigid and unreliable irrigation
rotation system. Many irrigation symptoms such as waterlogging have
been treated at a great cost to farmers and the public while the real
cause of the problem was the behavior of the farmer which, if
corrected, would have resulted in long-term improvements at lower
costs.









CHAPTER V


WATER SUPPLY AND REMOVAL


The water supply and removal subsystem includes the supply of
water from all sources for the farm system, delivery of water to farms,
and removal of water through the drainage system. Water supply
involves climatic data including rainfall and rainfall distribution, solar
radiation, air temperature, relative humidity, wind speed, and other
factors that influence the total amount of water made available to the
farm system. In addition, climatic data includes information about
hazards such as excess supplies of water from flooding (Figure 11).
Water supply and delivery is the conveyance of water from the
supply source to the farmers' fields. Water removal is the removal of
excess surface or subsurface water.
The institutional arrangements related to water supply and removal
are included in Chapter VI. Special attention is given to several
critical dimensions of the total area served. For example, topography,
land capability, and location of structures are included. These
dimensions may require development of detailed maps.


CLIMATE

Climatic Data

Most countries maintain some weather stations. It is preferred
that weather data are to be obtained from stations in close proximity to
the irrigated area. Types of data needed for collection include solar
radiation, air temperature, relative humidity, wind speed, open-pan
evaporation, and rainfall distribution.


Solar Radiation

Radiation from the sun not only furnishes energy for
photosynthesis, but is the primary source of heat for air and soil.
Solar radiation is sometimes measured as part of basic climatological
data. The basic measurement is generally recorded as calories/cm2 of











Canal

Water Supply
-Source
-Precipitation
-Surface flow
-Groundwater
-Conveyance
-operational control
-flow characteristics
-water losses
-farm inlet deliveries
-maintenance


Command Area
-Topography
-Land capability
-Cropping patterns
-Field and Basin size
-Location of structures
-General features
-wells
-pumps
-roads
-farm building


Collective Decision mal
Land use
Labor for maintenance
Water prices
Local practices
-settlement disputes
-work crews
-water trading
Cooperatives
Mutual aid


-Drainage
-Surface
-Subsurface


Figure 11. Idealized sketch of a farm irrigation water supply and removal subsystem.


Drainage Channel


a- i








incident radiation over a period of time and is generally reported as
monthly or seasonal mean values. Solar radiation data are primarily
used for calculation of evapotranspiration by various crops.


Air Temperature

Basic climatic data measured daily are maximum and minimum
temperatures, and are logged as mean as well as maximum and minimum
temperature. These data are usually summarized into weekly, monthly,
seasonal, or annual values. The data are needed to determine
appropriate growing seasons for crops in terms of time periods with
temperatures above a minimum and below a maximum, or in terms of
frost-free days. Temperature data are used to calculate growing
degree days (heat units) from daily temperature and are accumulated
daily for particular crops. For example, adjusted growing degree days
(GDD) for corn (maize) are calculated as the sum of mean temperature
-500F for each day. When calculating the mean temperature for a day,
any minimum temperature below 500F (10 C) is counted as 50 and any
with a maximum above 860F (30 C) is counted as 86. A day with 44
and 80 would have (50+80)-50=15 GDD or heat units. A day with 60
and 94 would have (60+86)-50=23 GDD or heat units. Corn hybrids
and some other crops tend to mature according to heat units produced
rather than an exact number of days. This adjustment process allows
for some vegetative growth in corn when temperature is above 50 F only
part of a day, with the best corn growth being at 860F with growth
beginning to taper when it is greater than 860F. Air temperature data
are used along with other climatic data to estimate evapotranspiration
for various crops.


Relative Humidity

Basic climatological data usually include measurements of relative
humidity. This is done by wet and dry bulb temperature determina-
tions or with a recording hygrometer. Relative humidity is one of the
determining factors in calculating evapotranspiration directly, or
estimating pan evaporation indirectly.







Wind Speed

Wind speed is measured with an anemometer and is usually
recorded as accumulated miles or kilometers per day and summarized
with other climatic data. Information on direction of prevailing wind
should be also noted.


Open-Pan Evaporation

These data are usually not included in standard weather
measurements but are collected within the irrigated area under study.


Rainfall and Distribution

Rainfall is usually measured once a day with a standard rain gauge
and occasionally with a continuous-recording gauge. Data from a
continuous-recording gauge is especially useful for giving information
about rainfall intensity. The data are usually summarized by month or
by a particular cropping season. Data can be plotted to show the
distribution of rainfall through a particular cropping season or
throughout the year. Data over several years can be used to calculate
probability of occurrence statistics that are useful for determining
irrigation requirements.


Weather Observation Stations

If sufficient climatic data are not available, it may be necessary to
establish a network of observation stations in a particular irrigation
area. These stations can be used to gather data for determining water
supply problems, groundwater recharge problems, irrigation
requirements, and crop adaptation problems.


Water Supply Problems

Data needed to predict yearly water supplies usually consists of
rainfall or snow depth, water content, and temperature measurements to
predict amount and time of runoff.








Ground Water Recharge Problems

If the recharge source of groundwater used for irrigation is
located away from the irrigated area, rainfall and possibly other data
are necessary to assess the amount of recharge water available.


Irrigation Requirements

Basic data helpful for determining irrigation requirements include
net solar radiation, temperature, relative humidity, windspeed, open-
pan evaporation, and rainfall. Irrigation requirements can be
summarized in relation to the above as

100(ET + LR)
IR = (Pe + Mc + Mg) + Lc

where IR is the irrigation requirement, Eta is actual evapotrans-
piration, LR is the leaching requirement, Pe is effective precipitation,
Mc is the carry-over soil moisture, Mg is groundwater contribution, E
is field irrigation efficiency in percent, Lc is conveyance and opera-
tional losses. The amount of data needed varies considerably from one
irrigated area to another. For example, only one measurement of solar
radiation may be necessary, but many measurements of rainfall may be
necessary if rainfall is variable over the irrigated area.


Crop Adaptation Problems

To study crop adaptation problems, much of the data already
gathered will be used. In most areas the climate usually fits into two
or more broad categories such as cool-season, hot-season, and cold
season. Minimum and maximum temperatures are needed for assessing
germination problems. Growing seasons can be categorized into frost-
free days, days over or under minimum, or over maximum temperatures
necessary for optimum growth of a particular crop. In addition,
number of hours of daylight and/or percentage of sunshine are usually
needed for photo-period-sensitive crops. Often this information can be
generalized from the latitude position of the irrigated area. The quality
of solar radiation is often of interest. Generalized information can
usually be determined from elevation measurements with the intensity of
shortwave radiation increasing as elevation increases.