The strategy options
Department of Animal Science
Dschang University Centre
B.P. 222, Dschang, Cameroon
This paper reviews strategies for matching feed resources to small ruminant production. Climatic, ecological and socio-economic conditions prevailing determine the types of strategy to adopt. Strategy options proposed include limiting small ruminant numbers to suit available feed resources, efficient use of natural browse resources, increased use of legumes in cropping and pastoral systems, integration of small ruminant production with tree crop plantations, more effective utilisation of crop residues and agro-industrial by-products, conservation of forages as silage or hay for use during periods of scarcity, strategic animal feeding schemes and use of fertiliser to improve forage yield where and when feasible.
Cette étude passe en revue les stratégies à suivre pour que les ressources fourragères puissant couvrir les besoins de l'élevage des petite ruminants. Le choix du type de stratégies a adopter s'effectue en tenant compte des conditions climatiques, écologiques et socio-économiques prévalantes. Diverses stratégies vent proposées notamment: diminuer les effectifs de manière à équilibrer le nombre d'animaux avec les ressources fourragères disponibles; tirer parti des espèces ligneuses spontanées; intensifier ['exploitation des légumineuses dans les systèmes agricoles ou pastoraux; associer l'élevage des petite ruminants a la pratique des cultures arboricoles; améliorer l'utilisation des résidus de récolte et des sous-produits agroindustriels; recourir à l'ensilage et au fanage afin de conserver les fourrages pour les périodes de pénurie; mettre en place des plans raisonnés d'alimentation; et, lorsque c'est faisable, utiliser des engrais pour augmenter les rendements fourragers.
Africa, excluding South Africa, has about 22% of the world's population of sheep and goats, and produces 14% of the total sheep and goat meat. Goat and sheep milk production in Africa also accounts for approximately 14% of the world production (FAO, 1981).
Small ruminants represent 24% of the total livestock units in Western Africa and 17% in eastern Africa (Peacock, 1985). Their distribution tends to favour the arid and semi-arid zones of tropical Africa where 58% of sheep and 68% of goats are found. Dwarf goats and sheep are more abundant in the humid zone of West and central Africa particularly as they have the advantage of being trypanotolerant.
Small ruminant production is typically a small-scale farmer activity attracting minimum investment in housing, feed and health care and is largely sustained by the potential of the individual breeds themselves. Three distinct management systems can be distinguished: free roaming (extensive) or herding, tethering and confinement of animals. Tethering and confinement are associated with areas characterised by high population densities, more intensive cropping, land scarcity and high labour requirements. In most of Africa, an extensive management system of production seems most popular for both sheep and goats. Among the numerous constraints to production under these systems, those related to nutrition are of primary concern.
The nutritional problem
Gatenby (1982) has indicated that the major factors limiting the productivity of small ruminants in Africa are poor nutrition in the semi-arid areas and diseases in more humid areas. Water can be a problem in some dry areas. Contrary to popular belief, the genotypes of breeds in Africa are not the primary limiting factors especially where nutrition, disease and marketing problems have been adequately handled.
The nutrient content in the form of metabolisable energy, digestible protein and minerals may be poor in arid and semi-arid regions, even when vegetation appears to be adequate. The dry season poses serious feed problems in semi-arid areas. There are three aspects of the feed problem, namely, the issue of increasing the efficiency with which the available feed is utilised (e.g. forages, crop residues, agro-industrial by-products and nonconventional feeds), the inability to make maximum use of the limited total feed resources and the inadequate supplies of feed (Devendra, 1987) and water.
Strategies for ensuring adequate nutrition of small ruminants must be based on optimising overall agricultural and livestock productivity from available resources, improving existing technologies and integrating technology that employs multipurpose crops and animals and recycling of crop residues and by-products as nutrients for both animals and plants.
Components of such strategies may include matching livestock production systems to available resources, selection of crops and cropping systems that will maximise biomass production and nitrogen fixation and thus minimise use of inputs external to the system, developing simple processing techniques to optimise the use of different components of crops for different end purpose, recycling of livestock wastes, making more efficient and widespread use of agricultural and industrial by-products as sources of ruminant feed and incorporation into the production system of non-ruminant species that are well adapted to use of farm resources, by-products and wastes. An in-depth analysis of each strategy is worthwhile.
De Boer (1982) reported that traditional producers, because of their small-scale operations, market few animals on ad hoc basis, if at all. Small-scale intermediaries handle the transport and assembly functions needed to make up economic numbers of animals for transportation to larger markets.
Experience shows that the scope for increasing offtake lies neither in attempts to regulate and control the market participants nor in the control prices, nor creation of parastatals but rather in facilitating the operations of the market participants and instituting measures which reduce marketing costs. These include, improving the infrastructure of livestock marketing, the provision of market information through the mass media (i.e. prices and volume of livestock traded in various markets), regulating the standards of products and services and negotiating favourable trade agreements in export markets (Solomon Bekure and McDonald, 1985).
Increased use of legumes in cropping and pastoral systems
Use of forage legumes in crop mixture
Intercropping forage legumes with cereals tends to increase the overall crude protein level of the total fodder available after grain harvest of the primary crop. Usually this involves undersowing a cereal crop with legume. The time of undersowing is critical to optimum production of grain and fodder. Mohamed Saleem (1985) indicated that planting Stylosanthes guianensis cv Cook or S. hamata cv Verano on the same day with sorghum reduced grain yield by more than 70%, but the loss of grain yield was minimised if they were sown 6 and 3 weeks, respectively, after planting the sorghum. Similarly, reduction in grain yields was observed in a trial in which sorghum was sown with Centrosema pascuorum, Alysicarpus vaginalis or Macroptilium lathyroides on the same day, but the reductions were not as significant as with S. guianensis.
Use of forage legumes to supplement natural grazing
Fodder banks have been suggested as a strategy to improve nutritional status of livestock in the dry season. Fodder banks are concentrated units of legumes established by pastoralists adjacent to their homesteads to serve as supplements to dry-season grazing. In Nigeria this has been developed into a low-input technology package for pastoralists by ILCA (Mohamed Saleem, 1985). Preliminary results on use of fodder banks appear to be quite promising despite some problems associated with establishment, utilisation and regeneration.
Use of forage legumes in crop rotations
Association of forage legumes in crop rotation has been demonstrated to improve the nitrogen content of soil thereby benefiting crop production when such plots are cropped. This also offers appropriate opportunity to integrate crop and livestock production. Mohamed Saleem (1985) reported that maize growth and grain yield was much higher when a portion of fodder banks of different ages was cropped as compared to yields immediately outside the fodder banks, which were previously either cropped or under natural sub-climax vegetation.
Better use of forage of tree legumes
Production systems using tree legumes usually consist of either a dense population of trees in a small area, a row of trees planted as "hedgerow" on bunds, as edges of crop areas or interplanted with crops (alley cropping).
The leaves of trees can be used as a high quality supplement to crop residues and grass. The level of incorporation may range from 20-75%. High responses in terms of weight gain have been registered with small ruminants (Home et al, 1986). Leaf production seems relatively unaffected by frequency of cutting although wood production is increased with decreasing cutting frequency.
Preston and Leng (1987) have indicated that tree legumes such as Gliricidia, Erythrina and Leucaena have a great potential as sources of legume fodder particularly as they are high-yielding perennials and possess deep-rooted systems that may have access to ground water and nutrients that may not be available to smaller leguminous plants. Rajaguru (1987) estimated that a hectare of tree fodder such as Gliricidia septum and Leucaena Ieucocephala could yield up to 6-8 tons of dry matter per year which could support 12 goats or sheep. Meanwhile, Horne et al (1986) estimated forage yield of G. septium and L. Ieucocephala at 12.1 tons/hectare/year.
Small ruminant production in an alley-cropping perspective has been analysed by Sumberg (1985). Alley-cropping is a system in which crops are grown in alleys between rows of frequently pruned trees. The large input of nitrogen and organic matter from tree foliage can potentially support continuous cropping at intermediate yield levels (Kang et al, 1981). Small ruminants can be integrated into an alley cropping by cut-and-carry feeding of portions of the tree foliage or by grazing natural fallow regrowth and trees during periodic fallow years. The cut-and-carry feeding applies to goats and sheep while the grazing system is limited to sheep because goats tend to de-bark the trees. Fast growing leguminous trees like G. septium and L. Ieucocephala are essential for the system of feeding. In order to give sufficient benefit to the crop and avoid the possibility of soil mining, it is recommended that approximately 75% of the available tree foliage be applied to the soil as mulch while the rest is given as feed to animals. An annual tree foliage yield of four tons dry matter/hectare would yield about one ton dry matter which is sufficient to support approximately 14 adult animals per hectare as a year-round supplement or four animals/ha as sole feed. Van Eys (1987) cautioned that structural carbohydrates are usually high in forage supplements. When their levels are high, this tends to interfere with the utilisation of roughage as well as supplement. In addition, there are some antiquality components in forage supplements (tannins, cyanogenic glucosides, nitrates, soluble oxalates) that can reduce palatability, voluntary intake and productivity if forage supplements are fed continuously to small ruminants, and particularly if they are fed in the fresh form or grazed by the animals. Some of these compounds can be partially destroyed by drying or storage. However, ruminants tend to be suited to utilising some forage legume supplements that contain antiquality substances since these can be detoxified in the rumen (for example, mimosine DHP in L. leucocephala).
Effective exploitation of natural browse for the nutrition of small ruminants
In Africa, it has been estimated that over 250 million head of domestic animals live in arid, semi-arid and mountain zones where browse is an important qualitative component of the livestock diet (Le Houérou, 1978). The widespread traditional use of browse as an available source of quality feed during the dry season is vitally important to maintain seasonal and yearly stability of livestock production. Lamprey et al (1980) have reported a browse productivity rate of 5000 kg dry matter/ha/annum for riverine Acacia xanthophloea which is about double that of most savannah grasslands. However, there is a large variability in productivity within populations of browse species depending on the ecological conditions. Established browse plantations of Medicago arborea have been able to produce 3500 kg dry matter/ha/year under annual rainfall of 350-450 mm (Le Houérou, 1975).
Otsyina and McKell (1984) indicate that browse, especially in the savannah vegetation types, contributes a large amount of available forage as a complementary source of feed for livestock, particularly during the dry season when herbaceous forage is in short supply. The major problems appear to be inadequate management systems that fail to make optimum use of shrubs and find ways to increase the number and quality of valuable browse species available for livestock production. Le Houérou (1980) reported that compared with tropical grasses, browse is richer in protein and some minerals in the dry season. At this time, browse plants are the most valuable feed used by livestock. Browse could therefore supplement the low protein content of grass forage if used effectively during dry periods. The crude fibre content of browse also tends to be lower than that of grasses and usually ranges from 20-40% and is even lower for shoots and leaves (Pellew, 1980). Given the low content of crude fibre in browse compared with dry grass, the energy content of browse appears to be higher than that of dry grass (Le Houérou, 1978).
Browse plants can satisfy the needs of small ruminants on provided that the animals can gain easy access to them and a sufficient quantity is available to them directly or with the aid of man. From dry to humid tropical Africa the contribution of browse towards intake by an animal implies considerable effort on the part of herdsman in activities such as planting of browse trees, maintaining the necessary balance of the species present by selective bushclearing and making browse available to animals by either beating down fruits as in the Sahel, by trimming or cutting back (Boudet and Toutain, 1980).
Carew et al (1980) reported studies on the potential of browse plants in the nutrition of small ruminants in the humid forest and derived savannah zones of Nigeria. Savannah goats and sheep browsed and grazed longer and spent less time scavenging than their counterparts in the humid forest. The biting ratios of browse to grass in the forest zone were 77:1 for the goats and 13:1 for the sheep. This shows that browse plants were selected more by goats and sheep in the forest zone than the savannah region though browse plant height or accessibility tended to affect selection pattern. Common species studied were Ficus exersperata, Newboulotia leavis, Asphilia africana, Spondias mombin and Cyclicodiscus gabunensis.
Recommendations (Otsyina and McKell, 1984) for research on browse plants include the identification of superior browse species with regard to available productivity, nutritive value and persistence under grazing by livestock; the development of methods for establishing desirable browse species in ecologically favourable areas along with grasses in mixed plantings; the improvement of management practices of established and native pastures containing both browse and grass species to maintain effective species composition; and the documentation of characteristics useful for improving shrublands for small ruminants in different seasons.
Integration of small ruminants in plantation crop production
Tree crops may contribute to livestock feed resources through use of their by-products. If these by-products could be collected properly and processed, they could offer alternatives to costly concentrates. Common by-products obtained from plantation crops include coconut cake, palm-kernel cake, rubberseed cake, citrus wastes (pulp, seed meal) and cocoa pods and residues. Cover crops grown in plantations also offer feed that can be used for small ruminants. Natural herbage growing under plantation trees may be collected and conserved in the form of hay. Where possible, controlled grazing underneath tree canopies may be practiced on a rotational basis. Fodder cultivation under plantation crops can also be practiced.
Wan Mohamed (1987) has indicated that cultivation of cover crops in plantations in Malaysia offers a lot of potential for production of small ruminants. The age of rubber trees or oil-palm trees tends to influence the botanical composition of the ground cover. Cultivated legume cover crops tend to decline as the trees mature due to- their shading effect which reduces photosynthesis. In terms of compatibility, sheep production is more compatible with oil palm cultivation than goats. However, both species are complementing in reducing the need to use herbicides and thus reducing the cost of weeding and increase returns per unit area of land.
Parawan and Ovalo (1987) reported that integration of livestock production with coconuts has a high potential in the Philippines. Moog et al (1977) indicated that coconut plantation pasture is available throughout the year and provides of farmers with nutritious feed for livestock. When feeds are scarce, farmers use coconut fronds in addition to bamboo leaves, banana leaves and Gliricidia septum.
The low technology inputs, the versatility in the feeding habits, and the relatively low acquisition cost of goats and sheep can fit appropriately into the majority of smallholder coconut farms. The added value of goat meat and milk, mutton and animal manure as fertiliser produced from the use of crop products, crop by-products and forage under coconut can raise the average income of the coconut smallholder (Parawan and Ovalo, 1987).
The constraints of integrating small ruminant production in rubber and oil-palm plantations include damages to young plants especially at establishment time, the potential toxic effect of herbicide sprayed on tree crop planted in rows and rat-baiting in oil-palm plantations which could contaminate by-products of oil-palm processing which could lead to copper toxicity problems in livestock (Pillai and Tan, 1977).
In countries where there is large-scale cultivation of citrus, their by-products offer useful feed resources for livestock. When grapefruit (Citrus paradisi) and sweet orange (Citrus sinensis) are industrially processed on a large-scale to produce juice or sections, by-products such are peels, rag, and depending on method of processing, other by-products like citrus molasses and citrus seed meal may be available. In most cases, the harvest of citrus usually coincides with the dry season when grass is scarce. When quantities of peel and rag (the string axis and white fibrous membrane) are large, they are conserved by drying. The dried citrus pulp can easily be mixed with other ingredients and is palatable, rich in nutrients and exerts a mild laxative effect. It can be stored for all-year feeding and deteriorates less in storage than many other feeds (Gohl, 1978). The pulp is better used as pellets where possibilities for pelleting exist.
Banana plantations also offer important feed resources for feeding small ruminants. It has been estimated that, for every ton of banana picked and exported to the fruit market, about 750 kg are rejected as being either unsuitable or in excess of requirements. This discarded fruit represents 10 20% of the crop depending on the degree of culling and the amount of fruit that is rendered unusable by storms (Le Dividich et al, 1978). Most of this can be used as animal feed. Chenost et al (1976) reported that in ad libitum feeding of goats, when forage and bananas were offered separately in a trough, the two feeds were ingested in such proportions that bananas constituted 20 40% of total ingested dry matter. When bananas were blended with forages, the intake of both dry matter and digestible organic matter rose sharply from 0 20% with increasing dietary content of bananas; at the 20% level, dry-matter intake was higher for ensiled than for fresh green bananas with a peek of 1.8 to 2.2 kg/100 kg liveweight. Beyond this level, dry-matter intake remained relatively constant as bananas replaced green forage on a weight-for-weight basis, while digestible organic matter rose slowly. Banana leaves may also be used as forage for animals.
More effective use of crop residues and agro-industrial by-products
With increases in population pressure and the demand for more food and farmland, the use of crop residues and by-products is increasing. Straw, for example, is a valuable feed resource especially during the dry season. However, Preston and Leng (1987) believe that the feeding of straws, like most roughages, to ruminants is constrained by their slow rate of degradation and therefore low total digestibility, their low propriate fermentation pattern in the rumen and their negligible levels of both fermentable N and by-pass protein which is usually associated with their low intake.
The digestibility of straws can, however, be improved by either alkali treatment, ammoniation, treatment with poultry manure or feeding with green forage legumes.
Alkali treatment of by-products to improve intake and digestibility
Kategile (1983) described a simple method of treating roughages with NaOH that could significantly improve their intake and digestibility in small ruminants. However, the cost and availability of NaOH may pose an important constraint under rural conditions. It is hazardous if not well handled and is a pollutant to environment.
Urea supplementation (ammoniation)
Naga and El-Shazly (1982) reported that supplementation with urea can improve the digestibility of nutrients contained in supplemented material provided the level of urea is maintained at 0.5 to 2%. There are risks involved when urea nitrogen in the diet exceeds 30%. This may lead to potassium losses in urine resulting in the depletion of the animal's body supplies (Juhaz et al, 1976). Eventually, this can lead to depressed bacterial growth, decreased synthesis of the B-vitamins in the rumen, loss of appetite and cerebrocortical necrosis (Naga et al, 1978).
Ammonium hydroxide from urea appears to be safer to use than direct liquid ammonia or gaseous ammonia. When mixed with an equal weight of water, the mixture contains about 5% urea equivalent of dry matter on dry-weight basis. The solution can be kept in water and feed containers covered with plastic sheet to prevent exposure to air for 3-4 weeks. After this period the plastic sheet is opened to release ammonia that has been produced, and the material can be fed to animals.
Using animal wastes to improve intake and digestibility of roughages
Excreta from poultry are rich in N. mostly as uric acid which is hydrolysed to ammonia by rumen micro-organism.
Sha and Muller (1982) reported that poultry wastes used at the 25-40% level can meet most of the protein and mineral requirements in ruminant livestock. However, the use of poultry wastes in ruminant feeds tend to result in reduced microbial count, low dietary energy content, exposure to pathogens and high intake of antibiotics and chemotherapeutics that may be present in the waste. Incorporation of high energy feed ingredients such as molasses, root crops and grains can balance energy requirements and maximise utilisation of the non-protein nitrogen (NPN) fraction of the wastes; mixing molasses with ration containing poultry wastes may improve palatability and intake and prevent eye and respiratory problems associated with the dusty nature of poultry waste. Pathogens could be eliminated by ensiling, stacking, formaldehyde in treatment or dehydration. Feeding of wastes that contain high levels of antibiotics and chemotherapeutics should be avoided.
Increased exploitation of lignocellulose as animal feed
Large quantities of lignocellulose from sugar-cane, timber and cereal processing usually go to waste. Feeding materials that are high in lignocellulose tend to have a low digestibility, low nitrogen content and low animal production potential. Simple inexpensive treatments which increase lignocellulose breakdown in the rumen and supplements of non-protein nitrogen could significantly increase animal production. However, when subjected to 3-6% sodium hydroxide solution and/or steam treatment, irradiation, grinding and ammoniation, lignocellulose breakdown in the rumen is increased, and with the addition of non-protein nitrogen its utilisation increases and thus improves animal production. Wong et al (1974) reported that treating bagasse with high pressure (14 kg/cm2) steam for five minutes raised dry-matter digestibility from 28 to 60%.
Conservation of forage as silage for feeding small ruminants during the dry season
Conservation of forage as silage under proper conditions can result in the preservation of 90% harvested energy and protein and the concentration of energy within the silage (McCullough, 1978).
In tropical Africa the use of sewage is not common. It, however, offers a good opportunity to preserve abundant forage produced during the wet season for use in the dry season. Under rural conditions, silage can be made in pit silos which are relatively easy to construct and are also affordable by farmers. Recently, there have been improvements of silage-making using discarded fertiliser plastic bags.
The chopped grass is compacted in the bag and sealed. All the bags are then packed and compacted in the silo after which the silo is sealed. This system enables farmers to ration the daily require silage by simply removing one or more bags as required. Empty fertiliser bags cost about 0.3 US dollars in local markets.
Silage-making is most convenient in high population areas where pastures are scarce and grasses like Tripsacum laxum and Pennisetum purpureum are readily available. Where sugar-cane tops are abundant these could also be ensiled. Under rural conditions, labour may be a serious constraint if large amounts of silage are to be made without mechanisation.
Increased conservation of feed as cut or standing hay and supplements for use in the dry season
Where animals are prevented from migration during the dry season, feeding strategies must be evolved that will prevent the animals from losing weight. Quite often some of the pasture is ungrazed during the wet season and retained for use during the dry season. This is called standing hay. This would require suitable supplements in order to maximise its efficiency of utilisation. Diets based on molasses/urea mixture may be employed to supplement dried standing hay (Gulbrassen, 1985). Whole cotton seed is occasionally used (Ngo Tama et al, 1987) in sheep rations in the semi-arid regions in North Cameroon. Similarly, cotton seed and groundnut cakes may be fed with straws, cut fodder or hay (Njwe, 1978; Fall et al, 1989).
The use of non-protein nitrogen (NPN) with standing hay has also proved most effective in dry-season feeding. Urea is most commonly used. The primary concern in feeding urea is providing sufficient amounts to be of value to the animal but minimising the risk of mortality from toxicity. NPN may be fed to animals by spraying on pasture in the field. The spray usually consists of 39% molasses, 6.25% urea and 54.75% water. This method is wasteful. Alternatively, the urea/molasses mixture may be fed separately as liquid in troughs placed in pastures, but the risk of poisoning, as each animal has free choice, is high. Block licks (40% urea, 10% molasses, 2.5% trisodium phosphate and 47.5% salt) have been used (Alexander et al, 1970). Molasses blocks of relatively low urea content can be used during droughts as high energy feed (Preston and Leng, 1987). The hardness of the blocks restricts and slows rate of intake.
Alexander (1978) has recommended incorporation of biuret in dry licks that contain salt. First, a 1:1 biuret to grain mixture is made. This is then mixed with salt in a ratio varying from 1:1 to 1:3. This mixture has been used to arrest decreases in body weight of sheep grazing dry poor quality pasture in Australia.
Use of fertiliser to improve pasture yields
On soils with low fertility, fertiliser application can increase dry-matter production per unit area. Superphosphate and nitrogen fertilisers like urea and ammonium sulphate are most widely used. Usually, fertiliser application is adopted in intensively managed systems in which high value products can justify the economic cost. The smallholder in most cases cannot afford the cost of using fertiliser, but farmyard manure from goat and sheep pens may be used in promoting higher pasture yields for a cut-and-carry intensive system of small ruminant production. Common fodder grasses that may be exploited in such a system include Tripsacum laxum, Pennisetum purpureum and Panicum maximum.
Unimproved pasture will continue to play an important role in small ruminant production in Africa. Overgrazing must be avoided to prevent degradation of these pastures. However, since these pastures become markedly deficient in quality, they are better utilised in the dry season with supplements such as ureamolasses, tree-forage legumes, leguminous browse, conserved legume hays and crop residues like groundnut and cotton haulms. Dehydrated poultry excrete from caged layers can also be exploited in supplementing poor quality forages during the dry season. It seems to be an economical protein supplement for ruminants especially as the cost of dehydration is low when compared to the cost of conventional feeds. A destruction of possible pathogens in poultry wastes needs to be done before it is used.
Quite often there may be competition for the use of some crop residues and agroindustrial products between livestock producers and industry. The production of paper from rice straw and alcohol from molasses, and the use of bagasse as fuel are common examples. This could easily render these feeds unavailable for livestock. Alternatives have to be identified and exploited to sustain livestock during a period of scarcity.
Conservation of herbage and surplus by-products by ensiling, drying or other means ensures a continuous supply of fresh and conserved feed over prolonged periods. Preservation of by-products of citrus industry either by ensiling or drying can make important contributions to the amount of locally available feed resources for small ruminants.
The cultivation of legumes in cropping systems may be hindered by the limited quantities and unaffordable prices of seeds. Commercial seed production which is a specialised activity, needs every encouragement by African governments. Several indigenous and introduced legumes and grasses need investigation in order to recommend suitable species for cropping systems and pasture improvement.
Grazing sheep can help control weeds on rubber estates and provide income to smallholders (in smallholder schemes) during pretapping years. Optimum carrying capacities for different aged plantations need to be determined. Sheep seem to be more compatible than goats when reared on a semi-intensive basis in rubber and oil-palm plantations. Both species are suitable for coconut plantations.
Silvipasture offer potential feed resources for small ruminant production in densely populated areas with forest reserves. Goats tend to adapt better to silvipasture than sheep.
The feeding strategy to adopt will depend on factors such as climate, ecological conditions, topography, farming systems and prevailing socio-economic conditions.
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