Practical technologies for mixed small farm systems in developing countries

by C. Devendra and H. Li Pun

INTRODUCTION

In animal production systems, sustainable agricultural practices are those that promote systems in which there is efficient use of the natural resources based on an understanding of the interrelationships within prevailing agro-ecosystems. These need to be identified with agricultural and rural development processes that have an integrated approach to natural resource management in which potentially important technologies are technically appropriate, economically viable and socially acceptable to target beneficiaries, the small farmers.

In small farm systems, the objective of achieving sustainable animal production involving crops and animals assumes two major considerations. Firstly, it is essential that the available animal genetic resources within the mixed small farm systems will be fully exploited in a manner that is consistent with their biological attributes and potential productivity. Secondly, the choice of practical technologies should be realistic of the needs of such systems in order to promote sustainable productivity, as well as provide economic stability.

The prevailing circumstances suggest, however, that these factors are far from being in place and is reflected by the a) inefficient use of ruminants (buffaloes, cattle, goats and sheep), b) few examples of systems that are demonstrably sustainable, and c) concurrent low animal productivity. The problems are complex especially in small farms. These farms are limited by both access and availability to adequate resources. The situation is further exacerbated by the growth of both human and animal populations, rural poverty and environmental degradation; all of which emphasise that the choice of practical technologies are especially important and can considerably influence the sustainability of the system.

Another dimension concerning sustainability is the livelihood of the farmers themselves. In extreme situations where land sizes are particularly small or where landless labourers or tenants are involved, ownership of animals provides the only means of sustaining their livelihood. Nomads, pastoralists and transhumant peasants fall into this category. In all regions, but notably in north Africa, Middle East and north Pakistan, India and China, to whom ownership of animals is the key to livelihood and survival. In these situation, sustainable practical technologies for animals assumes even greater significance in socio-economic terms.

It is appropriate therefore to examine the role of animal production in small farm systems and, in particular, to identify practical technologies that can significantly contribute to more sustainable systems and environmental integrity. The choice of technologies needs to take cognizance of the importance of crop-animal interactions where both components are complimentary and beneficial in terms of productivity from the land.

The purpose of this paper is to focus on those technologies which have been used in various developing countries and which show potential value. Specific case studies are cited in Asia, Africa and Latin America which highlight the relevance of these technologies in small farm systems involving crops and animals.

SIZE OF HOLDING

Farm size is an important consideration and actual size varies between and with regions and countries. Table 1 shows that in Africa, North and Central America and Asia, the highest percentage of holdings are less than one hectare in extent. In Asia and Asia the majority of holdings are less than 5 ha.

Table 2 illustrates differences between countries within Asian. The smallest farm size occurs in Bangladesh, while households cultivating paddy in Sri Lanka have average holdings of 0.3 ha of land.

Associated with the size of small farms, is the marked imbalance between the total ruminant livestock units and the available permanent pastures between regions. In Asia including centrally planned economies, the situation is especially critical where livestock densities are the highest in the world (FAO, 1986).

These small farms constitute the backbone of traditional agriculture throughout the developing countries (Devendra, 1983). Small size presents a serious constraint, partly because of lack of access to resources, but more particularly, because of the difficulties of promoting the application of practical technologies capable of a discernable impact. Thus, the small size of the farms determine, to a large extent, by the scale and extent to which new technologies can be adopted, and this aspect needs to be considered in the formulation and application of suitable technologies.

PRACTICAL TECHNOLOGIES

Notwithstanding holding size as a constraint to production and sustainability, there exist a number of practical technologies that have been tried with varying degrees of success. Really good examples of proven and demonstrable technology are, however, few. This is partly because they have been inadequately tested on-farm with farmers, but more particularly, because chosen technologies have not been considered in a holistic and systems context. Nevertheless, several potentially valuable technologies are apparent and these will be discussed in the following sections and can grouped into two broad production systems:

• situations involving arable cropping systems, and

• situations involving tree cropping systems.

TABLE 1

DISTRIBUTION OF SIZE OF HOLDINGS BY REGION IN THE DEVELOPING COUNTRIES (FAO, 1971)

* Establishments with no agricultural land which raise livestock and livestock products

Table 2. Variation in the size of small farms in some countries in South East Asia (FAO/UNDP, 1976)

⁺ US$ = 8.50 Rs (approximately)
⁺⁺ US$ = 285 Won (approximately)
* 1 rai = 0.16 ha
** US$ = 26 Baht (approximately)

SITUATIONS INVOLVING ARABLE CROPPING SYSTEMS

The Three Strata Forage System

In dryland farming areas, a major constraint to higher productivity from ruminants is the unavailability of good quality feeds especially during the dry season and periods of drought. The development of feeding systems that can increase the supply of good quality forages are, therefore, especially important to improve the prevailing low level of animal performance.

This is exemplified by the situation in Bali which has approximately three million people and three rainfall zones. Twenty five per cent of the land area is semi-arid with a rainfall of 900–1500 mm/yr. Farmers constitute about 70% of the total population and most of them practice mixed crop-animal farming. Among the ruminants, Bali cattle are particularly important and, in the dry parts of the island, income from livestock accounts for between 29–43% of total farm income. Farmers generally own 2–3 herd of cattle which are used for draught and beef production.

The feed resources for ruminants in Bali come mainly from native grasses, tree leaves and cereal straws. The dry matter productivity from these resources is generally very low (approximately 2–2.5 tonnes/ha/yr). Dry matter yields can be increased through the introduction of improved grasses as well as forage legumes, eg. leucaena (Leucaena leucocephala) and Gliricidia sepium.

Bali cattle generally feed on wayside grasses and crop residues. Live weight gains vary between 100– 200 g/day and marketable weights are only reached in about four to five years. However, with improved feeding and concentrate supplementation, it has been shown that daily weight gains of Bali cattle could be increased to between 400–600 g/day and that the fattening period could be reduced to less than two years.

These circumstances led to the development and successful demonstration of the Three Strata Forage System, a project supported by the International Development Research Centre (IDRC) of Canada. The system involves a first stratum of grasses and ground legumes; a second stratum of shrub legumes; and a third stratum of fodder trees.

The project ran for five and a half years and several relevant results were found comparing two types of systems: The Three Strata Forage Systems (TSFS) and the non-TSFS (NTSFS) at two stocking rates (2 and 4 cattle/ha). The results of the project have been published (Nitis et al., 1990; Lana et al., 1990; Arga, 1990; and Nuraini, 1990). Table 3 presents some of the results, and the following summarises the main highlights:

• The allocation of 0.09 ha of land as a forage boundary within the TSFS produced 98% more forage than the 0.25 ha of natural pasture. With the additional 2000 shrubs and 42 trees, the total wet and dry seasons forage production in the TSFS was 91% more than that of NTSFS.

• Stylosanthes, Centrosema, Acacia, Gliricidia and Leucaena which were grown, provided increased dietary nutrients in the TSFS. Consequently, cattle raised in TSFS gained 19% more live weight and reached market weight 13% faster.

• The availability of increased forages also enabled higher stocking rates and live weights to be achieved: 3.2 animal units (375 kg)/ha/year in the TSFS compared to 2.1 animal units (122 kg)/ha/year.

• Cattle in the TSFS were less infested by endoparasites. This was presumably due to less contact with the traditional cattle, since the TSFS cattle were always kept in confinement.

• The introduction of forage legumes into the TSFS reduced soil erosion by as much as 57% in the TSFS compared to NTSFS. Additionally, the fertility of the soil in the TSFS was also considerably improved.

• With the presence of 2000 shrubs and 42 trees lopped twice a year, firewood production from 0.25 ha of TSFS was 1.5 tonnes per year and TSFS supplied 64% of the farmer's requirement.

• Farmers in the TSFS spent less time managing their cattle and, more importantly, these same farmers benefitted by an increased 31% income compared to NTSFS farmers.

Further research and development aimed at creating a more sustainable TSFS will involve the introduction of goats. The justification for including goats is a) the official promotion of goats in dryland farming areas, and b) the potential for generating additional income. Additionally, goats will provide greater flexibility of resource use by farmers. On a live weight basis a 375 kg Bali bull is equivalent to 6 30 kg goats. When feed is limited during the dry season, it is easier to reduce the number of goats rather than cattle. Theoretical calculations suggest that with shrubs and tree fodders, increased carrying capacity is feasible and detailed studies are continuing on the utilisation of Gliricidia as a forage.

Table 3. Comparative Productivity of TSTS and NTSFS Plots (kg dry weight/plot per year) (Nitis et al., 1990)

⁺ Three strata forage system
⁺⁺ Non-three strata forage system

Food-Feed Intercropping

The concept of food-feed intercropping in both lowland and upland small farm systems is relatively new. The two principal advantages are: a) that the system aims to provide sustainability through involving the complimentary role of crops and animals; and b) the use of appropriate forage crops provides fodders and crop residues which are valuable both ruminants and non-ruminants.

Already several attempts to develop food-feed systems have been undertaken notably in the Philippines and Thailand. Rice is the principal cereal crop, but other crops which have been used with the aim of increasing the production of animal feeds include: cowpea, maize, groundnut, pigeon pea, sorghum and sweet potato. The criteria for the choice of the inter-crop include inter alia: the type of animals reared, potential forage or crop residue yield, promotion of soil fertility, drought tolerance and extent of the dry season, shade tolerance in upland areas, ease of eradication and resource requirements. The strategy is to integrate within the rice cropping pattern (intercropping and relay cropping) other feed producing crops and forage crops without reducing the area of the land used. Figure 1 exemplifies this situation in the Philippines.

In the past, the general tendency has been to grow only one crop of rice in both the rainfed lowland and upland areas resulting in a low cropping intensity. Both areas are important for livestock production. Furthermore, the rainfed lowland rice areas occupy about 67% of the total land area in Asia and where the bulk of swamp buffaloes, cattle and sheep are found. The drier upland areas generally favour the presence of small ruminants, mainly goats, but also some large ruminants.

Rice and wheat straws are the main residues from cereal cultivation and these supply the basic diet for ruminants. They provide bulk and energy for maintenance but not production. The intake of these roughages is limited by their low crude protein content (4–6%) and low digestibility, which necessitates supplementation to meet production requirements. Additionally, the reduced feed availability during the dry season and associated weight loss and poor performance, necessitates the application of strategies to ameliorate the situation and increase available dietary nutrients.

In the arable areas, cereal straws (mainly rice and wheat) and other crop residues are the most available and cheapest feeds for ruminants. The greatest challenge rests with the development of effective and economic feeding systems which utilize the high lignocellulosic content of straws.

Table 4 illustrates the value of integrating two forages lablab (Lablab purpureus) and Clitoria ternatea. The latter is grown by farmers in northern Philippines after rainfed lowland rice as monocrop for green pods and forage. No differences were found in mungbean grain and residue yield. The combination of mungbean plus lablab (cv Rongai) gave the highest forage yield of 7.9 tonnes/ha.

Similarly, Table 5 illustrates the results of an experiment on maize-forage intercropping under rainfed upland conditions (Tengco and Carangal, 1987) involving varying plant densities. Four forage legumes were used: Stylosanthes guianensis CIAT 136, Macroptilium atropurpureum cv Siratro, L. purpureus cv Highworth and Desmanthus virgaties. Of these, Siratro gave the highest forage yield. The results demonstrate the value of intercropping with suitable forages to produce valuable feeds for animals.

Figure 1. Cropping patterns involving rice and food crop - forage intercropping

Table 4 Grain, Residues and Forage Yields of Mungbean and Forage Legumes as Monocrop and Intercrop Combinations in the Philippines (tonnes/ha) (carangal et al., 1988)

⁺ Coefficient of variation
⁺⁺ Least significant difference (P < 0.05)

Table 5. Yields of Maize and Forage Legume Intercropping at Three Plant Densities during the Dry Season in the Uplands, Philippines (tonnes dm/ha) Tengco and Carangal, 1987)

⁺ Coefficient of variation
⁺⁺ Level of significance

Relay Cropping

Relay cropping is an important means to increase the supply of feed for farm animals. In relay cropping, a second crop is planted into the first before harvest eg. the introduction of legumes (groundnut or pigeon pea) into a main crop of rice or wheat. The strategy can extend the supply of feed, possibly, throughout the year.

Integrated Pig-Ducks-Fish-Vegetable Systems

A sustainable system which is widely practised in South East Asia and China involves the integration of pig production with fish farming, duck keeping and vegetable production, or a combination of these (Devendra and Fuller, 1979). The inter-relationships between the components are illustrated in Figure 2. The system is based on the use of ponds which not only meet the needs of pigs, but also enables fish and ducks to be kept. Water is also useful for vegetable production.

Such systems are especially suited for small farms where only a few pigs are reared together with either ducks or fish and intensive vegetable production. Edwards (1983) estimated that 26.7 laying ducks or 8.2 pigs or 0.8 dairy cow or 1.7 buffaloes are required to produce a mean yield of 174.7 kg of fish/year in a 200 m²pond, based on equivalent nitrogen manure inputs.

SITUATION INVOLVING TREE CROPPING SYSTEMS

Integrated Animal and Tree Cropping Systems

Integrating ruminants with tree cropping systems, such as, coconuts, oil palm and rubber are important production systems which have not been adequately exploited. Livestock/tree cropping systems are common in the humid and subhumid regions where intensive tree-crop production is practised. Although such systems are not new greater attention is needed to ensure more complete utilisation of the land. The advantages of the system are:

• increased fertility through recycling of nutrients(dung and urine)
• weed and shrub control
• reduced use of herbicides
• reduced fertiliser wastage
• provision of shade
• easier management of the plantation, and
• distinct possibilities of increased crop yields and animal products from the land.

There is an estimated area of 20.3 × 10⁶ ha under tree crops in South and Southeast Asia which reflects the potential for this kind of activity (FAO, 1986). Many of the Pacific island territories, notably Papua New Guinea, New Hebrides, Fiji, the Solomon Islands and Western Samoa have large areas under coconuts and a potential for integrating ruminant production.

Malaysia provides a specific example of the economic benefits of integrating ruminants with oil palm where an estate has allocated a portion of the plantation to the workers for grazing their animals. For the first two years (1980 and 1981) only cattle were owned and grazed, however, in 1982 and 1983 goats were also introduced. This was done because of their economic importance and capacity to supply both meat and milk in the estate.

A comparison between the grazed and non-grazed area involving both young and mature trees is valid in that it involved both the same area of 71–135 ha and, more particularly, the fact that both areas were on the same soil type. The effect grazing cattle and goats was an increase 2.15–5.16 tonnes fresh fruit bunches per hectare per year over four years (Table 6). When translated into the total hectare available for grazing and sale value per tonne of fresh fruit yield, the economic advantage is substantial. The result in economic terms is similar to the findings in West Java of integrating sheep and goats under rubber. The presence of legume is of definite advantage and it has been calculated that the amount of nitrogen utilised by the animal and excreted in the faeces and urine increases with the presence of the legume cover.

Figure 2. Integrated pig - fish - duck - vegetable system

Table 6. Effect of Mixed Cattle and Goat Grazing on the Yield of Fresh Fruit Bunches in Oilpalm Cultivation in Malaysia (Devendra, 1986)

More recently, a study has reported the integration of goats with pine (Pinus insularis) in the Philippines (Penafiel and Veracion, 1987). A stocking rate of four goats/ha did not cause significant soil loss nor disturbance of soil bulk density, compaction and infiltration rates. Thinning of the pine stands increased tree growth as well as forage production. The daily weight gains were impressive and averaged 99 to 129 g/day/goat. The integration demonstrated a ecological and economically viable and sustainable farming practice for the forest dwellers.

Alley Cropping

Alley cropping provides another opportunity to integrate crops and animals as well as enhancing sustainability. The development of the system has the following advantages:

• maintenance and promotion of soil fertility
• increase the supply of animal feeds
• supply of fuelwood, and
• contribute to the development of all year round feeding systems.

Table 7 presents the results of a study in Nigeria involving leucaena (L. leucocephala), maize and grazing with goats and sheep. The effects of both alley farming and alley farming after fallow on the yield of maize grains were 30–70% higher than that of conventionally cropped plots. The results did not separate out however, the specific effects of the presence of animals and fallow.

Table 7. Yield of Maize Grain in Conventional Farming, Alley Farming and Alley Farming after a Two-Year Grazed Fallow in Nigeria (tonnes/ha) (Reynolds and Attah-Krah, 1989)

⁺ Involving L. leucocephala and grazing by goats and sheep

SUPPLEMENTATION

In many developing countries, regular feed shortages and droughts are common. In such conditions, subsistence feeding mainly on cereal straws results in reduced live weight and perpetual animal low productivity. Inadequate nutrition is also associated with delayed age at first parturition, increased parturition intervals, prolonged non-productive life and high mortality.

Strategic supplementation of energy, proteins and minerals offer an important means to ensure that animal performance is not reduced, especially during critical periods of feed shortages. Several alternative strategies have recently been pursued, with the objective of better utilizing low-quality forages for production (meat, milk or draught). Foremost in these initiatives are a variety of chemical pretreatments (Jackson, 1977; Ibrahim, 1983; Sundstol, 1984; Doyle and Pearce, 1985). Among these, urea treatment is currently the most widely used to improve nutritive value of straws. The result has been a shift from a subsistence to a maintenance levels of nutrition, achieved by increased feed intake and/or digestibility (Ibrahim et al., 1984), and occasionally growth (Perdok et al., 1984; Verma, 1983) and milk production (Davis, 1983) responses.

The use of forage supplements has been secondary to chemical pre-treatments and has been underestimated and not given adequate research and development attention. For a variety of reasons, this approach has enormous potential for ruminants, especially in situations where animals are abundant and varied. It is appropriate, therefore, to review current understanding of the use of forage supplements and the benefits of this strategy. There are many advantages concerning the use of these forages (Devendra, 1988) especially in mixed farms in the humid tropics:

• availability in the farms
• accessibility
• provision of variety in the diet
• source of dietary nitrogen, energy, minerals and vitamins
• laxative influence on the alimentary system
• reduction in the requirements for purchased concentrates, and
• reduced cost of feeding.

There are several good examples of such forages, especially legumes, that can be increasingly used in small farm systems. Leucaena, for example, provides a valuable source of protein, energy and sulphur for the rumen bacteria, as well as being used for fencing, fuel and mulch. Further important examples include: Acacia spp., Ficus spp., cassava (Manihot esculenta Crantz), erythryna (Erythryna spp.), gliricidia (Gliricidia spp.), leucaena (L. leucocephala), pigeon pea (Cajanus cajan) and Sesbania (Sesbania spp.).

The potential value of these forages has recently been reviewed by Devendra (1990) and a number of observations are worthy of mention:

• With all ruminants the use of various forage supplements consistently increased live weight gain or milk production ¹,

• in many instances the beneficial response (meat and milk) was associated with a reduced production costs,

• of the forage supplements used, legumes have been particularly advantageous, and

• in the majority of situations stall-feeding or cut-and -carry systems are most common than grazing situation,

With regard to large ruminants, the research on the value of forage supplements for draught purposes is sparse. In Thailand, the effects of breed (Murrah X Swamp and Swamp) and feed supplement (with or without) on draught (work or no work) was studied over six months. The concentrate supplement consisted of cassava chips and dried leucaena leaf in a 3 : 1 ratio and was applied at 1.5 kg/head per day. The animals without supplements were feed on silage. Over the first four months before the draught capacity was assessed supplementation, as one would expect, significantly stimulated growth rate in both breeds. Concerning working ability, Thai swamp buffaloes ploughed more than the crossbred Murrah, and supplementation increased the area ploughed. However, there was no significant breed effect. Neither were differences were found in the speed of ploughing between breeds or supplementation, although, there was a tendency towards faster ploughing for both breeds when feed supplements were used (Konanta et al., 1986).

In terms of practical application, a recent review of the benefits of including high protein forages supplements to the diet suggest the following optimum dietary levels (Devendra, 1988):

¹ Wong et al, 1987 clearly shows that Leucaena supplementation increases milk production and reduces feed costs.

ALL YEAR ROUND FEEDING SYSTEMS

The strategy to increase feeds within small farm systems should have the final objective of developing sustainable all year round feeding systems appropriate to the prevailing situations. In this quest, maximising feed production is essential and the following approaches are feasible:

• intercropping with cereal crops
• relay cropping
• food-feed cropping systems
• intensive use of available crop residues
• forage production on rice bunds
• alley cropping, and
• three strata forage system in dryland areas.

The key elements in the use of these approaches are the quantification of the feeds produced throughout the year and efficiency with which they are utilized by the available animals. The former enables the determination of feed balance sheets, the extent to which animals can be supported and identify the critical periods during which feed deficits need to be corrected.

The scope for increasing the efficiency of feed utilisation in innovative systems is enormous. More innovative feeding practices are necessary that can sustain all year round feeding in more intensive systems of production. These could include the various chemical pre-treatments, supplementation and the use of multi-nutrient block (Kunju, 1986). Processing (chopping and grinding) of some crop residues may be feasible in certain situations and, associated with this, the development of complete feeds (Reddy, 1987). An overriding consideration that will determine the value of these approaches is the demonstration of economic benefits. For successful application and acceptance at the farm level, practical technologies need to be simple, within the limits of the farmers' capacity and resource availability, convincing and consistently reproducible.

The need for more evaluative work especially regarding the greater use of fibrous crop residues. Onfarm animal research (OFAR) is probably the only accurate assessment of whether new technology packages are acceptable both economically and socially to farmers, since the technique takes into account the interacting components within farming systems.

OFAR is also a means of identifying and addressing the constraints to adoption of new feeding systems and the extent to which they contribute to sustainability (Devendra, 1990b). Two phases are involved:

Phase 1: Information needed by farmers and advisers:

• Choice of feeds,
• extent of availability and seasonal supply,
• nutritive value
• detailed information on constituents
• prediction of change during production
• capacity to meet production target, and
• capability of filling any nutritional gap
• strategic supplementation:
• on animal performance, and
• on sustainable production of the basal feed resource
• feeding system,
• level and type of production, and
• realistic production targets.

Phase 2: Mechanisms for delivering information to farmers:

• Methodology, a balance between basic and applied research,
• linkages between disciplines and institutions,
• demonstration of economic benefit,
• large-scale on-farm testing,
• in situ utilization
• farmer participation, and
• definition of a model for feed resource development.

Several criteria need to be considered regarding on-farm work and these include inter alia the following: production objectives, the treatments involved, the precise methodologies to be used, measurements to be undertaken, type and value of the inputs used and the output derived from the experiment, extent of farmer participation, issues related to the economic analysis of the results and marketing.

OTHER PRACTICAL TECHNOLOGIES

In small farm systems, farmers can resort to several useful and practical technologies. This is a rational means to diversity the use of meagre resources and spread the risks. A number of these that have been proven successful are briefly mentioned in the following sections.

Soaking

Wetting or soaking cereal straws is a common practice and helps to increase feed intake. The addition to soaking the inclusion of 1% urea solution will further increase the nutritive value of the straw.

The technique has also been used to increase the utilisation of sorghum grains fed native pigs in El Salvador, where pig production is mainly a family enterprise and over 80% are indigenous breeds. Sorghum is soaked for 72 hours to allow fermentation and to increase digestibility, it is then fed with forage supplements (Melanthera nivea, Ipomoea spp. and Desmodium spp.). The results gave feed conversion efficiencies of 4.6, 5.0 and 4.2 for these treatments compared with 7.6 for the control group fed only unfermented sorghum (Ministry of Agriculture and Livestock, and Institute for Nutrition for Central America and Panama, 1986).

Sun Drying

Sun drying of some feeds before they are fed is a common practice among farmers in certain areas. The main reasons for this are to reduce the water content to ensure adequate dry matter intake. Good examples are the water hyacinth (Eichornia crassipes) and sweet potato vines (Ipomoea batatas) both of which are used extensively for feeding pigs in South East Asia.

The other main reason is specific to cassava leaves (Manihot esculenta Crantz) which contains hydrocyanic acid and is toxic to animals. Sun drying freshly harvested leaves and root peelings reduces hydrocyanic acid levels through the interaction with sunlight; the cyanogen is released as gas. A similarly, wilting leucaena leaves causes the enzymic hydrolysis of mimosine to 3.4 (1 H) pyridone, eliminatingacute but not chronic toxicity. A similar change occurs when the leaves are dipped in warm water (Lowry, 1990).

Feeding Mixed Forages

Farmers throughout the developing countries traditionally feed a mixture of forages, especially to small ruminants. The underlying reasons are associated with reducing any toxic effects found in any one feed (eg. cassava or leucaena leaves) and increasing the variety and palatability of the diet.

Water Conservation and Crop Production

In many parts of the developing countries, water is a critical constraint to crop production and its effect on animals is reflected in relatively low productivity in the semi-arid and arid regions.

In Mexico, three types of reservoirs to capture run-off water were tested in goat rearing semi-arid areas: ponds, micro dams and micro water sheds. Rainfall figures of 83.4,84.2 and 69 mm of water were recorded for the three types at 40 cm of depth respectively. The control rows only had 56.5 mm of water. The higher water retention allowed higher dry matter (DM) yields of maize (1744, 1794 and 1518 kg/ha, respectively) than the control (373 kg/ha). It was also found that the use of terraces allowed a 150% increase in the planting area. Maize was planted for human consumption and the residues were used for goat feeding. The biomass yield was 9.07 tonnes DM/ha, equivalent to 81 kg of DM produced per mm of rain.

The efficient conservation of water has also enabled the establishment of large scale trials in farmer's cooperatives where water capturing has assisted the growing of Atriplex canescens for feeding goats (INIFAP, 1989).

CONCLUSIONS

Sustainable animal production is dependent on the choice and application of appropriate practical technologies. The scale and extent of the success of the latter is influenced by the size of landholding. Present evidence suggests that good examples of practical technologies that promote sustainable systems are few, and more development effort is necessary to demonstrate their potential value and impact. Such efforts need necessarily to consider the nature of the mixed farm operations, crop-animal interactions, viability of the system, efficiency in the use of meagre esources and opportunities for demonstrating impact.

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