Characteristics and costs of vegetable irrigation in Dade County, Florida

Material Information

Characteristics and costs of vegetable irrigation in Dade County, Florida
Series Title:
Economic information report
Lynne, Gary D
Williams, John Henry, 1950-
Reynolds, John E ( John Everett )
Place of Publication:
Gainesville [Fla.]
Food and Resource Economics Dept., Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida
Publication Date:
Physical Description:
iii, 23 p. : ; 28 cm.


Subjects / Keywords:
Vegetables -- Irrigation -- Florida -- Miami-Dade County ( lcsh )
Vegetables -- Irrigation -- Costs ( lcsh )
bibliography ( marcgt )
non-fiction ( marcgt )


Bibliography: p. 23.
Economic information report (Gainesville, Fla.) ;
Statement of Responsibility:
Gary D. Lynne, John H. Williams, John E. Reynolds.

Record Information

Source Institution:
Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location:
Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management:
All rights reserved, Board of Trustees of the University of Florida
Resource Identifier:
026829413 ( ALEPH )
10861443 ( OCLC )
ACG0247 ( NOTIS )

Full Text


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

3ary D. Lynne

John H. Williams

John E. Reynolds


Economic Information


,Re port 99

/ /
o "/ '>

C os' s
/ /-..


of Vegetable Irrigation

in Dade County, Florida

Food and Resource Economics Department
Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida, Gainesville 32611

October 1978


Water is important to vegetable production in Florida. Competition
for water supplies among several uses will have effects on the vegetable
industry. This report provides information on the costs of water use for
vegetable production in Dade County. The average annual cost per thousand
gallons was estimated to range from $0.40 to $0.90, comparable to costs for
residential and commercial users of water in the same area. Informed
decision making by the current water institutions will be a necessary in-
gredient to improved water management. The analysis provided in this
report adds to the set of knowledge needed.

Key words: Water allocation, irrigation costs, agricultural water use,
water institutions.


The authors wish to thank the many agricultural producers in Dade

County that so willingly gave of their time to help provide needed data.

A special thanks is also due county extension personnel in the Dade

County Extension Office for their advice and encouragement. This publi-

cation also benefited from the reviews of Roy Carriker, Arden Collette,

and Cecil Smith. Remaining errors in presentation and interpretation are

those of the authors.



LIST OF TABLES..................................................... ii

INTRODUCTION.......................................... .... ... ...... 1

AN ECONOMIC FRAMEWORK FOR ANALYSIS................................. 3

IMPLICATIONS....................................................... 7

SUMMARY AND RECOMMENDATIONS...................................... 14

APPENDIX.............. .......... ............. ........ .............. 18

Procedures for Calculating Water Level Estimates............... 19

REFERENCES ...... ............. .......... ... ...... ........... 23


Number Page

1 Average size of firms (acreage), yield, operating costs,
and investment levels for selected vegetable crops, Dade
County, 1975-76. 8

2 Average annual costs and investment levels by type of
irrigation system for tomato production in Dade County,
Florida, 1975-76. 10

3 Water per acre and costs of irrigation for all irrigation
system types by selected vegetable crops, Dade County,
1975-76. 12

4 Average irrigation water applied and annual costs per acre
inch by irrigation system type, tomato production in Dade
County, 1975-76. 13


1 Hypothetical water levels for three 40 acre blocks of
tomatoes in Dade County, Florida. 20


Gary D. Lynne, John H. Williams, and John E. Reynolds


Vegetable production is an important economic activity in Florida with

farm sales reaching $448 million in 1976 [3, page 12]. This represents 18

percent of the cash receipts from all of Florida's agricultural products

for that year. Tomato production generated the most cash value at $162.6

million (or 36.3 percent) of all vegetable sales and about 6 percent of

all farm sales. Dade County was a major contributor to this production,

with $85.0 million in tomato production [8]. Because of its location in

the southern-most tip of Florida, Dade County is a major supplier of

winter vegetables.

A readily available supply of water contributes greatly and is a

necessary part of the production of vegetables in the state. In the

south Florida area, including Dade County, about 67 percent of all vege-

tables were irrigated (calculated from data in [10]). In Dade County,

about 80 percent of all the vegetables are irrigated, with all the toma-

Based on total sales of $2.53 billion [4, page 1].

LYNNE and REYNOLDS are Assistant and Associate Professors, respective-
ly, Food and Resource Economics Department, Institute of Food and
Agricultural Sciences, University of Florida. WILLIAMS is a former Grad-
uate Assistant.

toes, squash, and cucumbers irrigated (from data supplied in [2]).2

Continued population and economic growth has put pressures on the

water resources of the state; as a result, water has not been always

available in unlimited quantities to the vegetable industry. In 1971,

there were shortages in the Dade County area. Vegetable producers were

asked to reduce withdrawals for irrigation [12]. It is expected water

availability problems could become severe in the southeast Florida area

by as early as 1980 [11].

The 1972 Florida Water Management Resources Act was passed to deal

with the problems inherent in a growing socio-economic system such as

that prevailing in Florida. Water management districts have been

created and Governing Boards appointed [1]. Consumptive use permits are

already required of irrigation in 3 of the 5 districts. The water man-

agement districts, in turn, have the statutory authority to restrict

water use to that approved on the permit or any lesser amount the

district deems appropriate at any given point in time [1].

As a result, the 1972 Act could have substantial economic impacts on

all agricultural water users, vegetable producers included. It is too

early to determine long run impacts. Estimates of future impacts would

be speculative. It is already apparent, however, that by requiring

consumptive use permits water districts and their Governing Boards are,

or will be, allocating water among competing uses over time and space.

This means at some point, assuming ever increasing demands on a finite

resource, the Governing Boards will have to make very difficult decisions

A similar situation prevails in southwest Florida. Virtually all of
the tomatoes grown in that area in 1969, for example, were irrigated [6,
pages 64-65]. About 75 percent of all vegetables grown in that area
received at least some irrigation water.

as to how much water to allocate to vegetable production in Dade County

as opposed to commerce-industry, residential, recreation, and environmental

demands for water in the county or area.

It thus becomes important for those concerned with water management

to understand the nature and characteristics of the various water using

systems. Decisions which affect the availability of water for vegetable

production should be made with adequate information regarding the impacts

of such decisions. Only informed decisions by the Governing Boards will

give adequate consideration to the well-being of the vegetable industry

and the relationship (and contribution) of the industry to the public


This publication reports on the costs of vegetable production in Dade

County with particular reference to the relationship between these costs

and decisions regarding water use, management, conservation, and develop-

ment. Data for this report are derived from a larger study which has as a

major goal the estimation of the economic demand, and hence the economic

value, of water in irrigation. That effort is still in process.


Vegetable producers combine various factors of production to generate

a product to meet demands in the market place. Land, labor, water, capi-

tal (equipment, fertilizers, pesticides, etc.), and management are all

merged in a production process with the various interactive aspects of

nature to produce tomatoes, sweet corn, squash, pole beans, bush beans,

and other vegetables in the Dade County area. Water is an integral part

3ostof the results reported herein are from a study by Wlliams [13].
Most of the results reported herein are from a study by Williams [13].

of these production processes, and like all inputs to production, there

are costs associated with its use. More accurately, there is a cost

associated with use of the services of water just as there are for the

services of land, labor, capital, and management. The magnitude of the

yield per acre is a direct result of the manner in which these services

are organized and combined to produce a crop.

Some substitution is usually possible among the various inputs to

production. At least over limited ranges, for example, more fertilizer

can be substituted for less water to achieve a given yield. Similarly,

it is conceivable that more capital and/or more labor could be substituted

for some water, thus reducing water use. Investment in more efficient

irrigation equipment could reduce water use. Similarly, a more highly

skilled and attentive labor force may be able to increase productivity

from any given amount of water.

Vegetable producers are currently using a particular mix of resources

that are the result of substitution decisions made over years of produc-

tion effort. This mix of resources has been influenced by trial and

error, research results, and purveyors of farm equipment and other farm

inputs. In addition to these reasons, vegetable growers have adopted

particular technologies in response to price and economic conditions pre-

vailing over time. Given opportunities to substitute among inputs in

production, relative prices of inputs play a role in determining the

least-cost mix of inputs required to achieve a given yield. If the price

of a resource is low relative to other resources, an individual attempting

to maximize profits will use greater quantities of that resource relative

to other resources in the input bundle. With respect to water, the

"price" has been the cost of applying the water to the field during the

production season. This "price" has probably been relatively low and

relatively stable over a number of years, encouraging the adoption of

water-using technologies and irrigation strategies that reflect this

relatively low price.

The past set of economic incentives has encouraged the use of large

quantities of water. Also, experiment station recommendations have been

to apply water with the aim of maximizing yield, given the level of other

resources applied (see, for example, [10]). This level of application

coincides with the profit maximizing level under conditions of "inexpen-
sive" (costs approaching zero) water resources. With no competing demands

for the water supply, such irrigation practices made good sense, both

from the standpoint of the individual irrigator and from the standpoint of

regional economic productivity.

Policies implemented by water management districts through their

governing boards could have the effect of changing the relative prices in

the input bundle (for example, by raising the cost of getting water via

requiring permits), causing resource substitution in vegetable production.

A change in the mix of inputs, in turn, is likely to cause a change in

yield per acre. Whether such adjustments produce a net benefit to society

depends on the extent of loss to vegetable producers compared to the gains

made by other users of water, resulting from a reduction in irrigation.

Projections of impact on vegetable production from increases in the

cost of irrigation water (or decreases in the availability of irrigation

water) requires knowledge of the marginal (incremental) costs and marginal

Strictly speaking, the water level associated with maximum yield
should be applied only when the "price" of water is zero. However, under
highly uncertain field conditions a recommendation of maximum yield water
levels may also be appropriate when water "prices" are very low, relative
to other input costs.

response (in yields) associated with incremental changes in irrigation

levels. Unfortunately, marginal cost and response data are not available

for vegetable irrigation, and their acquisition poses difficult problems

in estimation. However, estimates of average operating costs and invest-

ment levels for production of vegetable crops in Dade County were deter-

mined .in this study.

Limited inferences concerning probable effects of alternative cost and

availability scenarios for irrigation water can be drawn from average cost

data. With some qualification,5 we would expect the following to be

descriptive over the long run:

a) a change in the cost or::availability of water for irrigation
will have the greatest impact on the production of those crops
where costs for irrigation are a high percentage of total costs
per acre

b) a policy which affects the investment in irrigation systems will
have the greatest impact on those crops where the investment in
irrigation equipment represents a large portion of total cost

c) in the case where the marginal factor cost of water is either con-
stant or increasing, the average cost per gallon of water delivered
to a crop is a minimum estimate of its value in that use. Thus, a.
comparison of the "price" paid by irrigators with that paid by
residential and commercial or other municipal water users is possi-
ble from average cost data.

Such inferences shed light on the answers to such policy questions as:

a) Which of the vegetable crops grown in Dade County would be most
affected by an increase in the cost of irrigation water or a de-
crease in the availability of irrigation water?

The major qualifications are that the producers must be functioning
in a highly competitive industry (pure competition) and have nearly perfect
knowledge. In addition, the current producers would have to be in a long
run equilibrium position. These assumptions may be rather heroic for the
vegetable industry in Florida, and particularly in Dade County. However,
there is in fact a high degree of competition in vegetable production and
producers may be striving toward a long run equilibrium because of the
need to keep costs low to survive. Only further research can verify or
deny these contentions.

b) What types of impacts and changes are likely given increased
water costs and/or reduced water availability?

c) Can vegetable irrigators afford to pay as much for water as
residential and commercial or other municipal water users?


Production cost data were collected from Dade County vegetable

growers during the 1975-76 production season [13]. Data on tomatoes,

sweet corn, squash, pole beans, and bush beans were obtained. The number

of observations and acreage surveyed for each crop is presented in Table

1. For each firm, data on total operating costs, irrigation operating

costs, total equipment and machinery investment, irrigation equipment

investment, system type (drip or sprinkler), and some limited information

on amounts of water applied were gathered.

Annual irrigation costs as a percentage of total annual operating

costs, which may be an indicator of relative sensitivity to water supply

and price policies, varied considerably among the crops. Irrigation

costs as a percentage of total annual costs were lowest (at percent)

for tomatoes and highest (at 16 percent) for squash (Table 1). This

implies that output of squash would be affected relatively more by any

given change in the price or availability of water, barring consideration

of possible off-setting factors such as a relatively strong market price

for squash.

There was also considerable variation among crops with respect to

proportion expended on machinery and equipment investment and other costs.

This will be an indicator of sensitivity if the industry is near a
long run competitive equilibrium, To the extent there is divergence,
the percentage expended in different categories is not an indicator of
output response (see footnote no. 5).

Table l.--A si-rase size of firms (acreage), vield, operating cc;ts, and investment levels for selected vegetable-crops, Dade County,

No. Acres Boxes ---------------Dollars-------------- --------Percent-------- -----------Dollars---------

Tomatoes 1S 322 476 37 2287 30 283 (2637 1.2 10.7 11.9 393 153 546

Sweet corn 4 454 194 38 651 32 79 800 4.0 9.9 13.9 304 158 462

Sclash 7 218 173 34 941 30 154 1159; 2.6 13.3 15.9 370 149 519

Pole7 beans 7 356 306 42 1255 21 97 '415( 1.5 6.8 8.3 200 104 304

Bush b-=s 5 572 96 43 583 19 88 733\ 2.6 12.0 14.7 226 93 319

Number of individual observations obtained in the survey.

b.Rntal rate in area (For comparable land if owned land).

C'.nnual irrigation machinery and equipment costs (ME) represent an assumed 10 percent return (opportunity cost) and a 10 percent
depreciation charge on machinery and equipment investment.

Inclu'd.: interest of 9 percent on operating capital for the growth period of the crop: 14 weeks s for tomatoes and corn; 12 weeks
for squash:; .nd 10 weeks for beans.

eIrrigation equipment costs (ME), other irrigation costs, and .total irrigation costs as a percentage of total costs per acre.

The av.rge yield for the sprinkler irrigators was 465 boxes and for the drip irrigators 504 boxes.

Interpretation of the results is again similar. The results suggest sweet

corn output response would be the greatest for a reduction in annual costs

of machinery and equipment investment. Again, caution must be exercised

in use of this interpretation in policy matters, as it depends on long run

equilibrium positions being realized.

Tomatoes are grown under both drip and sprinkle (big gun) irrigation

systems in the area, permitting comparison of costs between two systems

on a given crop. The portion of total annual costs accruing to irrigation

averages s6 percent for drip systems and IM percent for sprinkler systems

(Table 2). This difference in percentages is not dramatic, but it suggests

that those tomato producers with sprinkler systems may be slightly more

responsive to changes in costs of irrigation water (Table 2).7 However,

slightly higher overall production costs and higher average yields for

tomatoes produced under drip systems suggest that other factors besides

relative irrigation costs for the two systems will influence the response to

changes in water policy.

Additional insights may be gained by comparing average water use per
acre and average cost per unit of irrigation water delivered by crop

The range in annual irrigation costs per acre was larger in both a
relative and absolute sense for the sprinkler systems. This may reflect
the relative age of the two system types in the area; i.e., the drip sys-
tems were all relatively new and all reflected about the same "state-of-
the-art" in terms of equipment types and operating characteristics. The
sprinkler systems have been used more years, with the possibility that
producers employ a wider variety of equipment type and age, and different
operating strategies causing costs to vary more.

The procedure for arriving at these estimates is discussed in Appen-
dix A.

Table 2.--Average annual costs and investment levels y *ype of irrigation system for tomato production in Dade County,
Florida, 1975-76

a a
Drip Sprinkler (big gun)

Average Per-b Standard Average b Standard
Item per cent Range deviation per Percent Range deviation
acre acre

--Dollars-- -------Dollars------- --Dollars-- -------Dollars------

Annual costs
non-irrigation 2451 80.5 1700-3003 528 2275 91.7 1863-3003 322
irrigation 594 19.5 354-1074 277 205 8.3 48-476 136
total 3046 100.0 2659-3358 314 2481 100.0- 1939-3252 359
M and E investment-
non-irrigation 459 72.6 178-821 230 368 71.9 174-901 188
irrigation 177 27.4 119-250 51 144 28.1 75-306 72
total 636 100.0 544-1,071 272 511 100.0 264-1,039 216
Acre inches Acre inches Acre inches Acre inches
Water per acre
irrigation 5.8 43.1 4.2-7.2 1.14. 11.1 61.2 7.0-15.4 2.4
precipitation 7.7 56.9 6.2-9.2 1.35 7.0 38.8 5.2-11.1 1.7
total 13.6 100.0 11.5-15.1 1.53 18.2 100.0 14.4-22.5 2.59

aThere were 5 observations on firms with drip systems and 13 with sprinkler systems.

bNon-irrigation and irrigation costs as a percent of total costs, for the cost estimates. Irrigation water
applied and precipitation received as percentage of the total, for the water per acre variable.

CIncluding 9 percent interest on production capital, a 10 percent opportunity cost on M and E investment, and 10
percent of M and E for annual depreciation charge.

"This is the investment level ner acre based on producer estimates of the current market value of machinery (1) and
equipment (E).

Syui~uAmnc \CI)

(Table 3) No dramatic differences among crops are a;.p :-re:- in the acre

inches of water appliedd during the production season, with 10 acre inches

for tomatoes and sweet corn and 7 each for squash, pole beans, and bush


i',. average "price". of water to "i. County was highest

for tomatoes at an estimated $1.19 per thousand gallons and lowest for

sweet corn at 41 cents per thousand gallons. Clearly, water is not "free"

to the i r r.:-ior. The -,:-ril.:e price paid by residential users in Dade

County in 1974 was $0.28 per thousand [5] and for commercial users :in the

county was about $0.80 per thousand gallons in 1976 [7].

The higihet-- average cost per thousand gallons was paid 1. tomato

growers-using drip systems. Drip irr>." t-r': paid $3.78 per thousand as

compared with $0.68 per thousand, or over 5 times the cost incurred by the

sprinkler irr;i irt.-.n (Table 4).

The unit costs in Table 3 were calculated from total annual costs in
Table 1 in the following manner:
ACA. -
1 A.
2 1
ACG. -
1 P


ACA. = average costs per acre inch for crop i

TC.' = total annual cost of irrigation per acre

A. = acre inches of water applied during the production season

ACG. = average cost per thousand gallons applied to crop i

F- = conversion factor, from icre inches to thousands oF
gallons, F = 27.1543.

Table 3.--Water per acre and costs of irrigation for all irrigation
types by selected vegetable crops, Dade County, 1975-76.

---Acre inches--- -------- Dolls---------------


Sweet corn


Pole beans

Bush beans
















Precipitation received at Hcnestead Agricultural researchh and Educaticn
Center, plus irrigation water applied (see the Appendi::).

ACA is "average annual cost per acre inch."

ACG is "average annual cost per thousand gallons."

Table 4.--Average irrigation water applied and annual costs per acre inch
by irrigation system type, tomato production in Dade County,

Drip 5.8 594.59 102.51 3.78







aACA is "average annual cost per acre inch."

bACG is "average annual cost per thousand gallons."

The much higher costs found for drip systems may have implications

for water allocation decisions at the water district level. The physical

efficiency of the drip system is apparent, with sprinkler systems using

nearly twice as much water. However, the economic efficiency of the drip

system needs to be examined further. The additional costs (on the z

to use the drip system were $389 per acre, or a cost of $73 for each acre

inch of water saved ($2.71/thousand gallons). The producer would bear a

substantial burden, then, to save water

It is, of course, conceivable the producer cost of $73 per acre inch

saved is justified, in a social efficiency sense. That is, if the

economic productivity in other uses of the 5.3 in.-'es saved exceeds the

economic loss to the tomato growers, economic efficiency is improved by

the switch to the drip system. However, the distributive effects (income

transferred from Lo:n'ato growers to other segments of the regional economy)

may not be socially desirable. In any case, it is very important to -....

there are distribute i.on and efficiency effects of decisions and recomr

resulting from water district actions. These economic effects must be

considered, in addition to physical efficiency, in such decision prot


A large proportion of all vegetables grown in Florida are irrigated.

Water of suitable quality and quantity is in demand by vegetable growers

throughout the state. This demand is in competition with the water demand

by resid rntial, commercial, industrial, recreation, and "natural" uses,

(Th implicit assumption of this analysis is that yields are i
under either system. Yields would have to be about 76 boxes per acre
(1975-76 prices) from the drip system to make th' t.wo systems comparable
.in I he c'conomic returns to lie farmer.

as well as for irrigation of other agricultural crops. The 1972 Water

Resources Act was passed to alleviate conflicts and reconcile diEferences

as the different water users compete for the finite supply of water, which

is becoming a more scarce resource with each passing year.

Producers were asked to reduce irrigation withdrawals in the Dade

County area in 1971. According to planning documents recently published

by the water district in the south Florida area, water "shortages" will

occur in the not too distant future. It becomes important, then, to under-

stand the major characteristics of vegetable irrigation systems ;a; a step

toward informed decision making regarding water allocation and management.

The well-being of all Florida residents, as well as those directly associated

with the vegetable industry, is better served by informed decision making.

This publication provides information on the costs of irrigation in Dade


The Framework used in the analysis is predicated on the fact that

services from various production inputs (labor, fertilizer, pesticides,

water, etc.) are combined in such a manner as to generate different yield

lcvels. There is, in fact, an economic optimum level of input usage asso-

ciated with the prices of resources and products although in practice the

optimum may be difficult to identify or to achieve. Resources or pro-

duction inputs can be and are substituted among one another as production

methods evolve to ultimately generate the maximum profit level of output.

The current "mix" of resources devoted to vegetable production in Dade

County reflects the efforts of growers over a relatively long period of

time to adjust to economic conditions given available technology and know-

tedge of production relationships. The water use levels and irrigation

technology, for example, probably reflect the fact that water has been

relatively inexpensive and readily available over a long term period. The

rules'and regul!aio-s that reflect the policies cf :ater zeanaement disti :

can cause resource substitutions rnd pr5oductic response Vhich ay or -ay

not be the hi-'- s valued or =ost desired pcsib-e result.

annuall (crop year) irrizaticn costs varied frc- SS. -- acre for

bush beans to .313 per acre for to-atoes. Irriat--- c-sts an a percent

of total annual costs ranged fro- S percent for pole beans ct 16 percent

in squash production, suggestin-. that squash production o-2 be the -ost

responsive to changes in the ccsts of irrigationn. io.evr, the-re -ere

several lii-taticns in the data, that are discussed further below.

Aver-age cost of 'water per acre inch applied varied from S11.10 to

$32.43 across the crops in survey. This :_ves a ra-e of S.1 to $S.19

per thoi.nd gallons, values which are very sim-ilar :c -water costs paid

by residential and commercial users in Dade County during the sa~e period

of time. Esti-ntes of average water applied ranked frc- 7 t: 10 acre inches

per acre, over all crop types.

Data were collected on drip versus sprirnlcr irricaticn costs and

features in tomato production. Drip irrigation used 6 acre inches c w after

per acre. as co-pared to 11 acre inches, by the srin-ker irriaz.trs. Drip

irrigators also expn-ded -ore for inputs and received -igher yields, on

the average, than their sprinkler irrigator counterparts, -,:Z:e Lr; c-ore

intense itiput usage by the drip irrigators.

?"*.-.r":c costs of irrigation water were $102 per acre inch under the

drip system as compared to $18 per acre inch with sprinkler systems. There

was also a large variability in water supply costs by irrigators having thet-

same type of system, Fsu:"-e.tin; diffrn .-e:-:4 in efficiency in the irri,::;;:tion


A survey report of chiM kind does not lend : --i :TI to *.,;: '.iity .e, -."

*i. .:::.' .-ng '-:i- : conclusions -' .'...'., there are several considera-

tions t!hi: evolve fIr : th.- ror.''tNing which provide in-~i'l.t as to whete

future research --f forts should be dir-.cec.!:

1. Annual irrf --t i.on. costs are not a large share of :-.s tot I annual.
.:~r- ictle production costs. 'i.'.c,.-.;, tri.- cannot be ignored; any
.significant increase in such costs will most likely lead
source substitution (reduced water use) and reduced ;--. :i_ ...

2. r-.- c levels resource use (ici.luJin'!i water use) and the
current mix of such use is rho- result a ;: term" :-'. -::.
.p..-rn-..-; by the tnv..,l r-, a riod during which water has been-re'adily
.:-.' Ir:.:'ion A:-Lr.,..i :_ and investment levels in particu-
lar irrig:it to, system Lype ,'rWi' ] J.. ,L -water in the
past. Th:.-, !!..:.:,r- in the "rules-of-the-game" toward higher water
cost and less water availnC'-: y .water 7-. .-:.. 'districts
would have n-,.:t ive -i'VC ct; on ve.:.-.oabiT production add the growers,
which may or may not be in the best interests of society.

3. Water is not free to '. .rt.ble''r.I in D0i3 County. In fact, the
costs of water use .:''..-.- higher than the costs borne by residential
Users. Also, for two of the crops, the-costs were -: g than for
c. '*'r'-Lal users,

4. The costs-of drip :irrTi.-;: L; were consider, -: .:- (over 5 : -.)
than sprinkler irrigation, for tomato i-i.-,.. ,rs. If yields were'the
;.-. this implies that economic .: :-'iiency '" the". irn level)
is considerably lower with the drip system, 'iC,- .' .. : ef.T- n
of O'itp F...l:o.-, however, is liilr.-r ()pr irnklers u.A;1 nearly twice as
much water). The income-distri.:Y': ?- .* economic -fficiency ef-
fects, must .e considered in addition to h: i -i- .'ci-., the
water -wa '.-'c.'T:' districts.

5. Data sources must be .l,...''lop1'd to, facilitate estimates .m ';-: ;.il
yield response and i.i'-.1: 1 costs. All *r:-.'. r:s concerned with pro-
fits should have knowledge.',' these marginal conditions. This is
'also true for the water r-. i m:',.:-mL 'districts .b1ar;-,..'d with ala .at in.,
water in the public interest.

- A enveat is also i.,cOrt L .t at this juncture: the notion that the r,''..'nn;.',

." total annual cost devoted'to ir'; ,itfIo can be :'- as aa measure oaut-'

put r' i'': m-' :.-:: ay be-tentous-. Its vni-'li~3 ". is tot:!" .1-:. .i'Alcn. on the

dttgre; to which '! i' o' L.. Lt. ,b i e i .ndtn try 'al.-'., Kt s the conditions of' a

purelyy, cne.nii,,-ve Industry in oni. run equilibrium. Only further res~arc

can give answers to these issues. 1hr economic 7" -' .:1 quantity of water

use in vegetable production also cannot be deter-i-ed fro- these results.

The estimated after r use levels herein were based c several assutions,

discussed in tihe Appendix. C .ly further research, -here due conideration

is also given the economic di-ension, :ill generate data en the appropriate

water de-and levels for vegetables irn D'e Conty.

'emc:;,ble sro--ers -ust and :.ill adjust t. changrin. ecor--ic ccnditions.

The prevailing water institutions influence the "rules-of-th, -a-e'" which

in turn ;:rfect these, conditions. This publication is a first step toward

help ing both the grov:er and the --ter manager better understand the eco-

nom.ics oi vegetable irrigation, --h ich should ultiL-tely inprcv decisions

re;,ardi::r' after r management.




Very few of the producers surveyed had records of water received (from

precipitation) and/or applied with irrigation systems [13]. Thus, an

estimation procedure was necessary, based on each producer's best estimate

of how much water was actually used (or how long a pump was operated) on

each acre. Producers were asked to describe their irrigation strategy.

Most indicated a fixed strategy with smaller amounts applied per week during

"startup" times and larger amounts (again fixed amounts per week) applied

during the growing season for the crop. Generally, most producers indi-

cated approximately one inch of water was applied per week during the bulk

of the growing season. Some producers indicated if an inch or more of

precipitation was received during any particular week they did not irrigate

that week. This knowledge was used in conjunction with estimates of

precipitation received at the Homestead Agricultural Research and Education

Center to estimate water used on a particular acre for a particular pro-

ducer. The procedure used is best illustrated with reference to Appendix

Table 1.

A hypothetical situation is depicted in Table 1. The hypothetical

tomato producer has a total of 120 acres planted a week apart, starting

with the llth of October. This gives three weeks of harvest starting with

the 10th of January and completion of harvest during the last week of

January, starting with the 24th of that month. This hypothetical irrigator

is shown to pump 15 minutes during the first week (right after planting)

and to pump 45 minutes each week (except when an inch of precipitation is

received) until the last three weeks, when each well is pumped 50 minutes.

The approach used in calculating the water use from the data in

Appendix Table 1 is represented by the following set of equations:

Ap;enALx Table l.--lypothetlcal water levels for three 40 acre blocks of tomatoes in Dade County, Florida

Planting, irrigation, and harvest datesb

s a ells 10/11 10/18 10/25 11/1 11/8 11/15 11/22 11/29 12/6 12/13 12/20 12/27 1/3 1/10 1/17 1/24 Total

( (ai) P M P M P H P M P M P PP M P M P M P M P M P M P. H P M P H Pi
----------------------------------Units------------------ -----------------------------------

41 25 .20 15 1.19 0 1.20 0 1.08 0 .05 45 .03 45 0 45 0 45 1.19 0 0 45 .14 45 .26 50 .06 50 .02 50 5.42 435

41 25 1.19 0 1.20 0 1.08 0 .05 45 .03 45 0 45 0 45 1.19 0 0 45 .14 45 .26 50 .06 50 .02 50 .08 50 5.30 470
4' 25 1.20 0 1.08 0 .05 45 .03 45 0 45 0 45 1.19 0 0 45 .14 45 .26 50 .06 50 .02 50 .08 50 .02 50 4.13 520

12- --------- ----------------------- Not Calculated--------------------------------- --------------- ------------------------------------ ---- -. 14.85 .1.425

aMeasured in acres.
bDates used to signify the entire week of activity.

CPrecipitation () measured in acre inches received for the week and minutes (M) wells pumped during the week.



WI = (F )(C) E H M. (1)

WP = Z A P. (2)

WT = WI + WP (3)

A = A. (4)

IWA = (5)

PWA = (6)

W = IWA + PWA (7)

where (all variables defined for a firm for a season):

WI = total water used for irrigation, in acre inches,

F-1 = conversion factor from gallons to acre inches [F-1=(1/27,154)]

C = capacity of irrigation pumps, in gallons per minute,

H = number of wells in block i, i=l, 2, ..., m,

M. = number of minutes each well pumped in block i,

WP = total water received from precipitation, in acre inches,

A. = acreage in block i,

P. = precipitation received on block i,

A = total acreage in tomatoes over the entire season,

WT = total water used on the farm, in acre inches,

IWA = average irrigation water applied per acre,

PWA = average precipitation received per acre, and

W = average total water use per acre of tomatoes, in acre inches.

The hypothetical data presented in Appendix Table 1 is used in the following

to illustrate the procedure. Given an assumption of pumps capable of

yielding 1,000 gallons per minute, Equation (1) becomes:

WI = (1/27,154) (1,000) [(25 x 435) + (25 x 470) + 25 x 520]

= 1,312 acre inches.

and for (2):

WP = (40 x 5.42) + (40 x 5.30) + (40 x 4.13)

= 594 acre inches.

Equations (5) and (6) give (as A = 120):

IWA = 1,312 = 10.9 acre inches

PWA = = 5.0 acre inches

Thus, the average total water use per acre by this hypothetical producer is

given by:

W = 10.9 + 5.0 = 15.9 acre inches.

This is the water use on a "typical" acre, as defined in this study. Note

that M. = 0 (no irrigation) during weeks where P. > 1.0 (for example, the
1 1-
week of 12/6, Table 1).


[1] Carriker, Roy and Gary D. Lynne. "The Florida Water Resources Act of
1972: A Synopsis, University of Florida, IFAS, Water Resources
Council, WRC-10. Gainesville; 1978.

[2] Dalton, J. "Water Use Table by Crops." Homestead, Florida: Dade
County Cooperative Extension Department, March 1976.

[3] Florida Crop and Livestock Reporting Service. Florida Agricultural
Statistics -- Vegetable Summary, 1976. Orlando: March 1977.

[4] Florida Crop and Livestock Reporting Service. "Florida Cash Receipts
from Farming." Orlando: September 1977.

[5] Lynne, Gary D. and Kenneth C. Gibbs. Demand and Pricing Policy for
Residential Water. Food and Resource Economics Department,
Economics Report 83, Gainesville: University of Florida, December

[6] Lynne, Gary D. and Clyde Kiker. "Water Use in Southwest Florida: An
Economic Perspective." Food and Resource Economics Department,
Economics Report 82, Gainesville: University of Florida, November

[7] Lynne, Gary D. and William G. Luppold, and Clyde F. Kiker. Water De-
mand by Retail and Service Business Establishments, Dade and
Monroe Counties, Florida. University of Florida Agricultural
Experiment Station Technical Bulletin 800. Gainesville: 1978
(in press).

[8] McGuire, John F. "Value of Agricultural Products in Dade County 1975-
76." Homestead, Florida: Dade County Coop. Ext. Dept., 1976.

[9] Pride, R. "Estimated Use of Water in Florida, 1970. U.S. Geological
Survey Info. Circ. 83. Tallahassee: 1973.

[10] Rogers, J.S. and George A. Marlowe, Jr. Water Needs of Florida
Vegetable Crops. University of Florida, IFAS, Water Resources
Council, WRC 2. Gainesville: 1977.

[11] South.Florida Water Management District. Water Use and Supply
Development Plan -- Executive Summary. West Palm Beach: April,

[12] Storch, W. "Water Management During Drought Events." In-Depth Re-
port, 2 (April 1974) West Palm Beach: Central and Southern
Florida Flood Control District.

[13] Williams, John H. "An Estimation of the Agricultural Demand for Water
in Dade County, Florida. University of Florida, 1976.