THE ANIMAL COMPONENT IN MAIZE-SORGHUM FARMING SYSTEMS
IN CENTRAL AMERICA
Joaquin Larios, Jose Arze, and Roberto Arias
Centro Agronomico Tropical de Investigacion y Ensenanza
Turrialba, Costa Rica
In the semiarid zones of Central America, the small- and
medium-sized farms have developed a maize-sorghum/animal
production system in response to the predominant environ-
mental. characteristics. Management of the system and the
structure of its components are based primarily on environ-
mental v ar ia t ion s, soc ioe cononi c structure and level of
Available information on this system deals mainly with each
component independently. There have been few studies of the
relationships among components in this system, or in the
analysis of inputs (income) and outputs (products)--although
it is a very well-known system within poor farms in areas of
high demographic pressure (100 to 200 inhabitants/km2).
The search for alternatives that will help these farmers
requires a knowledge and u nder sta nd ing of the system to
better analyze the alternatives within their own systems and
to be able to suggest those that will have an impact.
The system described in this paper has been generally called
"Maize ( Zea mays L. ) intercropped with Sorghum (Sorghum
bicolor L. Moench)" (maize and sorghum). A list of common
names used in Central America follows:
Name Country (ies)
Maiz and sorgo El Salvador and Guatemala
Maiz and maicillo El Salvador, Guatemala, and Honduras
Maiz and million Nicaragua
In every country where this system is used, it is closely
related to animal production systems. Therefore a more
complete and descriptive name should include its animal com-
ponent(s). In areas where very small farms (up to 2 ha)
predominate a common mixed pr od uc t ion system is ma ize +
sorghum + cattle.
Although maize and sorghumn are the most important food crops
produced in the semiarid regions of Central America, other
food crops such as bean (Phaseolus spp. ), cowpea (Vigna
spp.), and fruits are important in specific areas. In other
areas, cash crops such as henequen (sisal) (Agave spp .),
sesame (Sesamum ind icum L.,and linseed (Linum usitatis-
simum L.) are widely cultivated and compete with maize and
sorghum for land. A list of animals found in this area fol-
Cattle (dual-purpose) Meat, dairy products, and powerl
Swine Meat and lard
Poultry Mleat and wa;is
The maize-sorghum/animal production system is generally
limited to the foothills near the Pacific coastal pllains,
rolling lands, and valleys of the interior of Central
America, as depicted in Fig ure 1. Northern El Salvador
appears to be the area where the system is most widely
cultivated. Of all the area cultivated with sorghum in
Honduras and El Salvador, around 93% is intercropped with
maize, and in Guatemala, 80%.
THIE PHYSICAL ENJVIRONMlENT
The Central American Isthmus extends from east to west with
the Caribbean Sea at the north end and the Pacific Ocean at
the south (Figure 1). Hot humid lowlands predominate on the
Atlantic coast. The interior is composed of mountains and
A wide belt of steppe conditions is found in the areas that
have mixed systems. Precipitation stays below 1,000 mm in
the interior valleys; this dryness is probably caused by
mountain valley winds rather than the shielding effect of
the mountains. In the coastal foothills, rainfall may range
from 1,400 to 2,000 mm; and in some areas, such as northern
El Salvador precipitation may be greater than 2,000 mm .
Annual rainfall is distributed in a bimodal pattern. The
dry period begins in November and ends in April or M~ay, and
the wet season is interrupted by a short dry period (called
canicula) in July or August (Figure 2).
Potential evapotranspiration is high; observed values range
between 1,000 and 2,000 mm. This results in a soil moisture
deficit through May and the use of soil reserve in July. In
the semnihumid areas, an excess of water is registered in
September, contributing to an increase in the availability
of residual soil moisture through December. In the semiarid
I Oxen used for pulling carts and soil preparation.
2 Chickens and some ducks and turkeys.
Figure 1. Distribution of Maize + Sorghumn in Central A\meric3
w. ;n Loc. Le. ? Jun J. 7.03. Op r~. Ir).
Figure 2. Water Deficient Periods. La Trompina, El Salvador
regions, the number of months with a moisture deficit ranges
from 7 tosl0; in the semihumid regions, the range is from 5
to 6 months.
Southeastern Guatemala, southern Honduras, northeastern El
Salvador, and northwestern Nicaragua correspond to what has
been described as semiarid regions. The agroclimatic
characters of these regions are similar to other semiarid
regions of the world. They can be summarized as follows:
o The beginning of the rainy season is uncertain.
o More than 90% of annual precipitation occurs during the
wet season, which generally lasts from 4 to 7 months.
o Precipitation during the wet season is often extremely
variable--not only _from year to year but also within
o The mean daily' rainfall intensities are 2 to 4 times
greater than in many temperate regions; the short dura-
tion intensities frequently exceed the intake capacity
of the soil.
According to Holdridge's classification, sorghum-based crop-
ping systems are found mainly in the following life zones:
(a) humid tropical forest with a biotemperature above 24 C
and (b) dry tropical forest in transition to subtropical
with biotemperatures below 24 C, but with an average annual
air temperature above 24 C (Figure 3).
The cultivation of sorghum seems to be closely related to
biotemperatures or air average annual temperatures above 24
Predominant Soil Types
The soils where the maize and sorghum cropping system is
cultivated can be grouped in three classes as follows:
o Class 1. Lands level to mod era tely sloping (15%) .
Deep soils, well-drained with low sus ceptibility to
erosion, generally free of stone hardpan or impervious
layers. The soil texture varies from- clay-loam to
o Class 2. Level land (Up to 8% slope), located in deep
valleys. Deep clay soils (up to 89 cm) with drainage
o Class 3. Steep lands, slopes up to 50%. Shallow soils
(30 cm max im um) with prevalence of loose stone or
shale, and highly susceptible to erosion.
The first and third classes (particularly the third) are the
most commonly used for crop production by small farmers.
Dlugram, for mle Classrfeohaon of
WoRLo PLANT rORMATIONSS OR NATURAL LFE ZONES
by L FI old**d a
LATIUDIN L \ o ATITUINA
esses Iuoir rt De \:1 so / g s o
,.~~~ -O -* --------
amOnce PP on .. ** ***
I~i / /3 // 1
..s--** I-* --------t -- "\1, \ \ '\ "1"
sea ad *r see go 0 5 ot
.........,,..... \uaaneo.un m \ ca e \ o a se ne \ hnt <0 Ubu
Fui gur 3. LieZoe it aorCncnrtino thei Miz Srl CrpigSse
Figure 4 shows an environmental profile for the association
of maize and sorghum in El Salvador Ni carag ua and H~on-
duras; considering annual rainfall, altitude, sloping, soil
fertility and depth.
The average farm family is comprised of 7 members, around
75% of them are under 30 years of age; in some areas the
population is somewhat younger (40% under 12 years). Assum-
ing that the women's inputs are 0.7, of a man's working day,
and the children's input 0.5, then the average farmer has a
daily equivalent of 5 man/days in his family.
Ed uca tion levels vary from country to country. In some
areas, literacy can be higher than 80%, in others, it may be
lower than 60%. Among children, it is generally higher than
in parental groups.
Farm size is considered to range from small to medium (0.25
to 70 ha). Land tenure is considered to be inadequate; in
some cases 75% of the farmers occupy 25% of the land. This
situation is rapidly improving due to agrarian reform plans
being conducted by governments of the Isthmus.
Cash flow in and out of the farm is very difficult to quan-
tify, especially cash spent on food, clothing, and health.
Farm expenses and farm activities are closely related to
farm size (Figure 5). In crop production, a small farmer (7
ha farm) may invest up to US$200 mainly on fertilizers (70%)
and other field supplies, and about US$45 on animal feeds.
Cash flow into the farms comes from activities realized on
and off the farm, as depicted in Figure 5. On small farms,
most of the income (around 75%) is obtained from the sale of
excess grains (maize and sorghum), dairy products, meat and
draught animals (bueyes). The importance of the animal com-
ponent in generating income increases as farm size increases
(Figure 5). Cattle are more common in larger farms, while
swine and poultry can be important sources of income among
the smaller farms.
Annual rainfall, mm
SO, IC00 100015 2000
S10 20 40+
Environmental Profile of the Maize Sorghum System in
three Countries of Central America. El Salvador,
Nicaragua and Honduras
Animal 80 f ammal pro farm jobs
produce t ob duction
1.6 ha. 11 ha.
708 Crop 613
an i a l Prcduction A nnial production
farm jobs o
60 ha. SO ha.
Figure 5. Prrcentace of Income Derivea from Farm Activities in
Different Farm Sizes (Unpoolished Data, CATIE, El
Facilities and Equipment
The value of fixed capital ( housing storage, fencing, and
animal shelter) is also affected by farm size; on the aver-
age farmers of these areas report holdings worth around
US $303O. Farm equipment is very scarce, a majority of the
small farmers own only a plow (Egyptian wooden plow) and
hand tools such as sprayers, hoes, shovels, and macanas or
bordones (a handweeding instrument used for planting beans
and sorghum into stands of maize). Average value of this
equipment varies from- 18~ to 403 US dollars. Very few farmers
own transport facilities other than oxcart.
FARM SYSTEM TYPES
The farm types of the maize-sorghum/animal production system
farmers are closely related to the climatic constraints
hydricc deficit), and the size of the farm.
As farms grow bigger in size, the areas dedicated to cattle
activities tend to increase, especially as related to crop
production areas (Figure 6).
On small farms, crop production systems constitute the main
activities since they are related to family subsistence.
W~ith the increase of the farm size, the areas dedicated to
crop pr od uc t ion are c omp ar at i vel y small--about 4 or 5 ha
(the maximum surface that can be managed by a farmer and his
On farms of more than 50 ha, there is a considerable
increase in crop production systems, since the farmer rents
part of the farm to be planted with maize and sorghum by
other farmers with less resources. In return, the farm
owner will receive cash, part of the crop labor in dif-
ferent ways, or combinations of these. The cultivated areas
managed directly by the farm owner tend to diminish to a
minimum level of subsistence.
The farm size is directly related to the availability of
water. Large farms are normally located in areas with less
available water whereas small farms are concentrated in
areas where more water is available.
In the small pr od uc t ion systems, maize is the main crop ,
normally associated with beans or sorghum. Pigs and poultry
are the main income-producing animals.
,........ Annual \': co,
0 10 20 30 40 50 60 70 80
Size of the farm (Mz)
Figure 6. Variation of Farm Activities According to Area withlI he
Variation of Farm Size in Tejutla, El Salvador
The increase in the hydric deficit modifies the cr opping
patterns; maize is displaced in importance by sorghum, for-
aepastures, or henequen. Swine and poultry are kept on
all farms, and there is an increase in the number of cat-
tle. The interrelations between farm size~i, b -aric deficit,
3..3 farming sys=< ae shown il Figure 7,~ all within a
representative area for the m~aize-tsorghu/am/aimal production
CROP PP.O)DUCTION SYSTEM 3'
The location of the cropping system (Figure 1) is very much
related to the frequency of uncertain rainfall periods in a
short summer or canicula. (Figure 2).
The farmers cultivating sorghum-based cropping systems are
usually poor and their farm enterprises are near subsistence
level. They have adopted cr opping patterns c;-at diminish
risk, but ensure food for their families. In this adapta-
tion process, it is very important that the chronological
and spatial arrangements of the cultivars used in the maize-
sorghum system be related to water availability. Figure 8
shows the relationship between rainfall patterns and rela-
tive growth of mnaize and sorgh um. The cr opping patterns
most often used are the following (Figure 8): (a) maize and
sorghum planted simultaneously in May; (b) maize planted in
May, sorghum planted 25 to 30 days later (at the fertiliza-
tion and hilling-up of the maize); (c) maize planted in May,
sorghum in July (during flowering of maize); (d) maize
planted in May, sorghum in August (at be nding of maize).
The patterns used are closely related to the cultivars and
to the water availability in the area. The crop spacings
more frequently found are (a) single rows of maize inter-
planted with sorghum, (b) single rowJs of maize and sorghum
both sharing the same hill, and (c) sorghum broadcast in
maize seedings (Figure 9).
The local maize varieties, because of their earliness (har-
vest at 80 days, tasseling at 46 days) have a greater proba-
bility of escaping the dry period. Local varieties, such as
criollo are better intercrops when cultivated in association
with sorghum. Moreover, these varieties serve well ei-ther
as grain and/or fodder. Sorghum local varieties are day-
le ngth sens it ive ; when planted in May they have a long
vegetative growth period due to long days between May and
July. In August and afterward, the competition with mnaize
is reduced and the days become shorter a condition that
favors the intensive growth of the sorghum (Fig ure 10).
This characteristic makes it difficult to replace the local
H. MAZE PASTURES
to CPG and /or
< 20 '/.of the fcrm
( mono r opi,)
_- -- --
--major animalls (bovine~s ) -- -----------
Figure 7. Interrelationship Among Size of Farms, Hydric Deficit and Farming Systems of Crops
and Animals in Small Farms of the East and North Zone of El Salvador
MAIZ E+ BEAN or M~AIZE+SORG
SORGHUM or and a monoc
KC------minor animals (swine and poultry)
A r J J A S O N: D E E
A MJ J 4 S O !1D E F M
II J J A, 5 0 0 O E D t: ; !
Ei-,ure 8. Rela3tion Between Spacial A\1rrangemouts anrd Relative Growth~
of~ the Manize/Sorgumm c~ultivncio~n Syste~ms with thec Rain
Distributioni in I:l S1lvaidor
a) ~ ~ cS Eqidstn Sigl Row
b)' Sigl Rows, Sorgh at Foo ofr Ma
c)'t Si g e R w f a z ,S r hu r a c s
11: 40 .
J F` M A M J J A S
\ S O N D J
J F M A ME J J
Fi::ure 10. Relaltion Between the Sunrise, Sunset. andi Durat~ion oft Dayv
Variation vieh thef Relative Growcn Va;r~inin:; of the Ma:i;:c
photoperiodic sorghum with day-length neutral sorghum; when
planted *simultaneously before August, there is strong compe-
tition between the crops since both have similar growth pat-
Cropping activities begin early in the year (Table 1) with
slashing and burning. After the first rains, maize is sown
and 10 days later fertilized with N and P; a second N appli-
cation is applied be tween 25 and 30 days after planting .
Amounts used vary from one area to another and sorghum is
Weeding is one of the most time-consuming enterprises of the
system. A first weeding is done 15 to 21 days after seeding
the maize. The aporco .(hilling up) also may be considered
a weeding activity. The last weeding is done just before
the planting of sorghum and/or bending over of maize
The maize is harvested between October and December; the
complete cob is removed from the field and shelled by hand
near the home. Sorghum panicles are cut at the base and
carried off the field to finish drying the grain. Threshing
is done by hand beating the panicles with a stick. Yields
vary considerably from one area to another depending on how
severe the canicula is in one particular area and how much
fertilizer the farmer uses, although some differences
probably are due to varietal yield potential.
ANIMAL PRODUCTION SYSTEMS
The farm with primary production based on the maize-
sorg hum/ an imal pr od uc t ion sy stem manage their animals in
two ways: (a) patio and (b) pasture.
Patio management is primarily used for small animals.
Animals wander freely around the house, with their proximity
to the house regulated by feed availability. Normally, such
farmers keep swine (from 2 to 8/farm). Frequently, hens are
kept (from 2 to 12/family); turkeys are sometimes present (2
to 3% of farms), as well as ducks on a similar scale.
The main characteristics of the typical animal production
systems of widely extended maize-sorghum areas in the Cen-
tral American Pacific area are as follows:
TABlE 1. TYPICAL CROPPING ACTIVITIES
Week* M~an -----
Month~ No Activity Days Type Quanitity Product Quantity
Mlar 9-15 (We ed in g 12.0 Organlic
Mattee (OM) ?
Apr 15-13 Burn 7.0 Ashes ?
;lay 18 20 Herbic ~Li die aippli ca tion 3.0 Paraquat 2.4 1/hia Mlulch ?
M:ay 18-20 PlanitincJ (Maize~) 3.2 Scod 16 kg/ha
May 19-21 Fortilizer application 3.0 N-P .0 to 20-20 kg/hia--
June 21-24 Wooeding for masize 3.61 -O.MI. 1000 kg/hia
003 1/ Planting (sorybum)) and Aporce 0.9 Seed 6-12 kg/hia
23-25 Fer-tilizer application 0.9 N 20 kg-
23-25 :](~ Woingi for maize 5.01 -O. M. ?
30-32 "Dobla~" or Despunte" maize 4.11 -O.II.?
anid wooding for sorghumn
36-38 Maiz- harvest 6.01 -Ears?
339-7 Mahi ze selcl Iing 5.01 -Cob~s and husk~ 331-1700 kg
52-59J Sorghium harvest 6.0I --Foragoe ?
Grain 570-1900 kg
1/ Socyhlum plantingl date has a widle rangec, Ecrom 30 to 90 days atftr planting thle ma~ize.
Sys tem Ma in Charac ter i sti cs (By Importance)
Cattle Pasturing, dual purpose Milk, cash
Swine Free and confined during Cash
Poultry Free management Eggs, cash, meat
Feed ing of the animals is a pr imary ac tiv ity consisting
mainly of obtaining and supplying crop residues. Other
activities include egg collection, processing, and sale of
dairy products and animals. Less frequent activities
include th~e sale of eggs, pigs, and poultry. Table 2
details such activities during the course of the year, and
Table 3 shows the inputs and outputs of a typical farm with
10 ha of pasture.
Table 2 and 3 show that the animal production systems
require a few specialized activities; these are readily done
by the family. The wife and children are usually in charge
of feeding the pigs and chickens, and the children can also
milk the cows and move them from one place to another on the
Farm an imal s are fed almost all of the crop s ubpr od uc t s:
the root system is the only component of primary production
that is not consumed This finding, plus other evidence
shown in the following chapter proves a high degree of
adjustment of the system to the physical and socioeconomic
environment that in many cases include not only material
relations but also affective relations between man his
animals, and his land. On these farms, it is very hard to
find cows without names, though this does not occur with
smaller animals because of the short time they stay on the
farm (usually no longer than one year).
The interactions be twee n the crop and animal pr oduc t ion
systems within the farm system may be classified as positive
or negative. The order of the following interactions is not
related to importance.
o Animal sales provide capital for crop production.
o Animal production absorbs labor not suitable for crop
o Failure in grain production due to the canicula allows
the farmer to use the maize in storage to feed animals.
ACTnIVITY J F MI A M3 J J A O N D
Feeding < T-- 7
1. Manize residues
2. Sorghum residues
3. Grazing n- -
4. Supplements & concentrates 3-
Crcmpoeam, butter and cheese
inimll sale -
II. Si:IZES I -
2. Crop residues
3. Mlilk residues
Live sale (2/year)
Graini feeding (ma~ize & sorghun)~
L C) C
TABILE 2. TYPICAL ACTIVITIES INi ANIMALL PRODUCTION
IV. GUA\TTERS CROPPI:G
STABLE 3. INPUTS AND OUTPUTS/YEAR IN ANIMAL SUBSYSTEMS (TYP-
.ICAL FARM OF TEJUTLA WITH MAIZE + SORGHUM/CATTLE/
SWJINE/POULTRY COMPONENTS. EL SALVADOR, 1980.
Quant ity/ Farm Qu an t ity/ An imal
IInputs from outside farm system
(a) maize grain
(b) sorghum grain
(a) sorghum grain
(a) concentrated feeding
(b) seed cotton meal
(a) pigs (2)
(a) chickens (5)
(a) two young (livesale)
30utputs to market
o Animals help complete the farmer's diet.
o Animals provide traction and manure for crops.
o The diversity in animal species allows more efficient
utilization of plant and animal products or by-
o Poultry helps control damaging insects.
o Cattle and crops compete for available land, capital,
o Swine and poul try cope te with humans for available
o Soil nutrients are carried off the field by cut and
carry crops (guateras).
o Cattle may compact soil and cause erosion.
Figure 11 shows a semiquantitative description of the maize-
sorghum/animnal production system and the interactions
between crops and animals. The system is depicted as having
o Cropping systems: maize-sorghum and guateras
o Animal production systems: cattle, swine, and poultry
o Socioeconomic systems
In this sys tem family labor participation is very imnpor-
tant. The maize-sorghum activities demand high labor use at
certain times, especially during weeding, planting, and har-
vesting activities, while labor distribution in the animal
production systems is more or less constant during the year.
In a mixed pr odu ct i on system (crop and a ni mal s ), f am ily
labor capacity is used more efficiently.
In the cropping subsystem, the maize and sorghum association
requires products from outside the farm, such as fertili-
zers, insecticides, herbicides and in some cases, seeds.
Production includes, basically, grains used as food for the
family and animals and the residues that are sold or fed to
the cattle. Swine and poultry use the damaged cob~s or
grain that falls in the field.
Another cropping system ( in addition to that of mnaize-
sorghum) that has not been fully studied is the guatera
cropping system. The farmer gives little attention to this,
especially to its planting and harvesting Forage- (fromn
sorghum and occasionally maize) can be cut and piled in the
field or consumed directly by the animals.
C( A SH II ~ `
M~alze Grain :~
Live rbiden (l
MAZ uAI aSORG)IHUM Plowing
SEEDIHC 0.5-5.0bas. ~ O
to3FERTIlLIZA- MA ZE/50RG)IHUM-lTTfE GR
Kg/ha TION 3.9m-d 0.5 to 3.5 hect R _d
Paraguat. PUBLICATION L IGU .1.
~iE[~D EEDIN;G 20m-d
2.Li Who 3 m-d 81L E Z -):
:r IIHUMANJ PO ER i
FAM nLY1 FEED (7)LAD
Rnli~cI to 10 anina~ (71)*
S LAYING2 to 8 animals
SI L Y. Iiii ;r300 eggs oCHICKEN(S
I~~il CHICrc(s 5. CONSUED OR SOL1
--- 5kg)(5)2 to 12
DMnE PREPARAT IG ?
IMP&nElitL) TW( L.L1E
FIGURE 11. A SEMIQUAIITITATIVE DESCRIPTION OF THEC MAIZEtSORGIUM/AN IMAL PRODUCTION SYSTEM IN CENTRAL AMERICA.
An imals are pr od uced for f am ily consumption and/or sale.
Milk, cheese, eggs, pork, and poultry meat are some family
consumption products. Pork meat, milkr, cheese, eggs, and
live animals (chickens, pigs, and calves) are for off-farm
sales. Common input expenses in animal production are for
salt and meal.
Little is known about cash flow in this production system.
There are many constraints to crop production systems, ani-
mal production systems, crop-animal production systems, and
farm systems. One of the main problems in discussing this
subject lies in setting a limit to the system to be ana-
lyzed Factors l im it i ng pr od uc t i vity in the semiarid
regions of Central America, as mentioned before, are many
and varied including environmental stresses (drought,
nutrient deficiencies, water, and wind erosion), biological,
social, and economical constraints.
Crop Production Constraints
From the above-mentioned restrictions, environmental stres-
ses, especially drought, limit crop production most. This
phenomenon occurs because of the variability in the rainfall
pattern and the canicula, which in some areas may last more
than 30 days. Drought is accentuated by the existing
phy s iog raphy shallow soils, and heavy soil textures. In
some areas, nutrient deficiency, particularly nitrogen,
phosphate, and sulfur, may reduce crop productivity and can
be related to drought.
Within the biological cons traints, the wJide use of lowc-
yielding varieties (criollas) of both maize and sorghum
reduce the possibility of increasing crop yields. Another
disadvantage df these varieties is that they are highly sus-
ceptible to downy mildew (sclerospora sp. and schlerophthora
sp.). Although a new disease (irtreported in the area in
1975), it has rapidly gained importance in some regions of
El Salvador, Honduras, and Nicaragua.
All the constraints for crop production activities directly
affect animal yield also.
Animal Production Constraints
Feed quality and availability are the primary constraints to
animal production. During the dry season, maize and sorghum
residues gn qateras are the only source of food since
p~astu~rc 7r-c? Lrr is Liit to the rainy season. The quality
ofE the feed$ may be poor, protein intake is low, and feed
is scarce, accentuating this constraint.
If feed availability is the m~ain constrain~t to the animal
prod uc tion system, then the m~ost imp~cor tan t constraints to
the ma ize-sorghum/animal system would be the same as those
listed for crop production. As crop production increases,
more crop residues are available, making more feed avail-
Farming System Constraints
The primary constraints-to the farm system are related to
availability of land, labor, or capital. Land availability
may change in the area due to the agrarian reform projects
be ing carried out by some of the g over nmen ts Labor is
limiting during short periods, especially at weeding times
and when high-paying off-farm systems ( coffee cotton, and
sugar cane) demand labor. Low capital availability is rela-
ted to the time crops are sold, usually immediately after
harvest (when prices are low), to buy commodi ties and to
plant the next crops. Thus, it is impor tan t that farmers
have cattle, swine, and poultry to be sold when capital is
Information on maize-sorghum/animal systems is relatively
scarce. Available data deal with the production of maize,
sorghum and animals independently--or to associations of
the maize-sorghum cropping systems.
The lack of quantitative, as well as qualitative, informa-
tion on inputs, outputs, flows, and components of the maize-
sorghum/animal system makes it difficult to understand its
structure and functions in time and space.
To find alternatives that help improve the system it is
o Limit the system to a particular farm or region.
o Identify the composition and ranges of crop components,
forages, (autotropic) in the predominant farms.
o Study the composition of the animal pr od uc t ion
o Study the variability of the crop-animal relationship
in the region and identify the interaction levels.
o Iden~ti fly, by levels, the use of human energy (family
and'off-f arm) for the management of the crop/cattle
relation of the maize-sorghum/animal system.
o Study the expectations that farmers may have about the
o Identify the 7physiobiological as well as socioeconomic
characteristics of the region where the system will be
The limiting factors that should be studied can be classi-
fied as follows:
o Analysis of the variability of the canicula, as
well as of the start and termination of the rainy
o Analysis of water retention capacity of the soils
used for the maize-sorghum/animal system.
o Evaluate the guatera cropping system.
o Evaluate the maize-sorghum system for human and
animal consumption. Quantitative evaluation:
amount of grain for family use and/or sale; amount
of grain, stubble, and guatera for animal produc-
tion Qu al it a tive e valuati on : quality of feed
for human and animal consumption.
o Make spatial and c hron olog i cal arrangements and
rotations that allow adaptability to the ecologi-
cal conditions of the region, as well as facili-
tating availability of the animal component feed
during the seasons of greater necessity.
o Test varieties and/or species to improve the quan-
titative as well as qualitative yield of maize and
o Improve the maize-sorghum system through (a)
drought tolerance, (b) high nutritional yield, (c)
low soil fertility requirement, (d) component sub-
o Manage and recover soils.
o Identify and evaluate breeds, animal species, and
management of the traditional system, emphasizing
qualitative and quantitative aspects.
o Identify and evaluate nonconventional forage
'plants, such as those used tr additionally in live
o Find ways of improving management of the animals
in the system.
o Evaluate (in vitro and in vivo) the maize-sorghum
o Quantify flow components within the system; esta-
blish inputs and outputs of the maize- sorgh um/
o Study the animal pasturing effects on lands
planted with maize and sorghum (compaction and
We wish to acknowledge the contribution of Ings. lod e sto
Juarez, Gerardo Petit A., and Enrique La Hoz for the infor-
mation made available to us, and to Dr. Raul Mloreno for his
suggestions and final revision of this work.