Abstract
Introduction
Materials and methods
Results and discussion
Conclusions
References
Sandra L. Russo
Mixed Farming Project, P.O. Box 2596, Banjul
The Gambia
The Gambia has a short rainy season (3-4 months) and a long dry season. The present practice of unregulated pastoralism and the lack of a land-tenure system results in under-utilisation of livestock and overgrazing of native rangelands. Prior to 1981 little research had been conducted in forage agronomy. The Mixed Farming Project, with its focus on livestock and maize production, started in 1981 and included component research on forages and range ecology. Legume introduction plots were established around the country in 1982. Only Stylosanthes species and a grass, Andropogon gayanus, have shown any promise under local conditions but communal grazing and no fencing has made deferred grazing or fodder banks impractical. Intercropping forage legumes with maize was begun in 1984 with a view to providing dry-season grazing. Although research station results, grazing and feeding trials show the excellent potential of forage legumes in The Gambia, until there is ownership of land farmers will not include forages in their farming systems.
The Gambia is the smallest country on the African continent, sandwiched into Senegal on the west coast between 13° and 14° N. The Gambia consists of land on either side of the river Gambia, never more than 30 km north and south of the river and running east from the coast approximately 300 km. Total precipitation has been 1000 to 1200 mm annually, but in recent years annual precipitation has dropped to 600 to 800 mm. The rains start in late June and last for 3 to 4 months. The long dry season of 8 to 9 months causes serious problems in terms of livestock feed resources.
A major survey (Dunsmore et al, 1976) estimated that the total dry season fodder resources in The Gambia were able to support about 177,500 adult cattle equivalents annually. The main fodder resources were: crop residues, floodplain grazing, early fallows and upland bushland. However, since 1974, the cattle population has increased from 200,000 to 300,000 head, the area of floodplain grazing has been reduced due to an increase in cultivation of irrigated rice, the population has increased by 3.4% annually, the areas formerly left fallow are beginning to be continuously cropped, and bushlands are being cultivated.
The Mixed Farming Project (USAID/CID/GOTG) started in The Gambia in 1981 with the objective of effecting a better integration of crop and livestock production, thereby increasing the availability of forage for livestock. The project has worked in three areas: maize production (grain for humans, stover for livestock), forage agronomy and range ecology, with supporting socio-economic studies. Prior to 1981 little research had been done on forage and range resources in the Gambia.
From 1982 to 1984 the forage programme concentrated on introducing legumes. Seed was obtained from CIAT and planted at three sites across the country representing three major soil associations. In 1983, the plantings were expanded using seed from the 1982 season. Also in 1983, seed from ILCA was planted in small plots at one site. Half-hectare plots were added at four Mixed Farming Centers, a rural training centre and at one village site. The survival of the accessions at three sites as of 1985 is shown in Table 1. None of the plots were irrigated or innoculated with rhizobia and only minute quantities of P were broadcast on the plots.
Table 1. Species, origin and survival of legumes in introduction trials at three sites in The Gambia, 1982-85.
|
Species |
Locationa |
||
|
Yundum |
Sapu |
YBK |
|
|
Stylosanthes humilis - local |
x |
x |
x |
|
Stylosanthes hamata - Australia |
x |
x |
x |
|
Stylosanthes hamata - local |
x |
x |
x |
|
Stylosanthes hamata - ILCA |
x |
|
|
|
Stylosanthes scabra - Australia |
x |
x |
x |
|
Stylosanthes guianensis - Australia |
x |
x |
x |
|
Stylosanthes guianensis - cv. Endeavor |
x |
|
|
|
Stylosanthes guianensis - cv. Schofield |
x |
|
|
|
Stylosanthes guianensis - CIAT |
x |
|
|
|
Stylosanthes macrocephala - ILCA |
x |
|
|
|
Stylosanthes capitata - ILCA |
x |
|
|
|
Stylosanthes capica - CIAT |
x |
|
|
|
Aechynomene histrix |
x |
x |
x |
|
Macroptilium atropurpureum |
x |
x |
|
|
Leucaena leucocephala - Australia |
x |
x |
x |
|
Leucaena leucocephala - local |
x |
x |
x |
|
Leucaena leucocephala - Philippines |
x |
x |
x |
a. An x indicates established, surviving plot as of July 1985.
Between 1982 and 1984 the range programme concentrated on developing deferred range areas for dry-season grazing and on improving those areas through seeding and root planting of grasses (Andropogon gayanus, Cenchrus ciliaris) and seeding legumes (Stylosanthes hamata and S. humilis).
From 1982 to 1985, feeding trials were conducted at the Yundum research station during the dry season with N'Dama cattle using various types of crop residues, including groundnut hay and stylosanthes hay. In 1983, a village-level feeding trial was started which used a combination of deferred grazing on improved rangeland and crop residues to feed cattle from January through June. This programme was extended to three more villages in the 1984/85 dry season but was restricted to the period of greatest feed shortage, between 15 March and 15 June.
In the 1984 planting season, an experiment was conducted on intercropping maize with cowpea (Vigna unguiculata), groundnuts (Arachis hypogea) and lablab (Dolichos lablab). During the 1985 dry season, two experiments with maize and cowpea were carried out under irrigation. For the 1985 rainy season, two maize/cowpea experiments, one sorghum/cowpea and one maize/stylosanthes experiment (S. hamata, S. humilis and S. scabra) have been planted at three locations, and one alley cropping experiment (maize, leucaena, gliricidia, and sesbania) has been planted. Also in 1985, a maize/cowpea intercropping package was introduced to 30 Women's Societies in the country and 15 on-farm maize/cowpea intercropping trials are being carried out by the Maize Unit of the Mixed Farming Project.
Legume grazing trials were conducted at three locations for several months in both the dry and the wet season in 1984. These trials used work oxen, sheep and goats and were primarily to determine the platability of the different legumes and to assess the animals' preference among the species.
Legume introductions
The introduction plots at Yundum, Sapu and YBK were kept weed-free. At the other sites, including village fodder banks, labour for weeding was available only sporadically, and these sites appeared to have been taken over by bush. However, a closer examination showed that the Stylosanthes species, S. hamata and S. humilis in particular, established almost complete groundcover below the bush. None of the other legumes persisted in the relatively untended plots. Even with weeding at the research station plots, many legumes did not survive, because of either inadequate moisture or failure to reseed. S. sympodialis, Zorina spp., Centrosema spp. and Desmodium spp. did not regenerate at any site. At Sapu, Siratro sp. regenerated, while at YBK and Sapu Aeschynomone sp. recovered. S. scabra was the most productive in terms of biomass, remaining green well into the dry season and greening-up quickly after the first rains, but it was unpalatable.
The performance of leucaena was disappointing. Germination was often poor even with seed treatment, seedling vigor was poor, rabbits and termites devastated many plots, maximum height after 3 years was 2 m with few branches, and it was unpalatable to all classes of livestock. However, it has been a prolific seeder. Research on this plant is continuing. The alley-cropping experiment mentioned earlier (with maize, leucaena, sesbania and gliricidia) will start with 6-month-old leucaena seedlings in an attempt to overcome the poor germination and low vigor of leucaena grown from seed. The Forestry Department is planting seedlings in village garden plots as fences and borders, and for use as fuel, fencing and feed.
Intercropping experiments
With increasing pressure on land around the villages and the decrease in amount of land under fallow, interest in intercropping of cereals and legumes has increased. Intercropping is a common practice in The Gambia, usually with sorghum and millet or maize and millet, but frequently with cereals and groundnuts and occasionally with maize and cowpea. Although research on intercropping has been conducted at Sapu for many years, no recommendations have yet been made to farmers.
Legume seed is in short supply, which is a serious constraint in the forage programme and even more so for farmers. Several experiments were designed for 1985 using cowpea as an intercrop with maize. Cowpea seed of several varieties is readily available, although it is expensive compared with other grains as it is a preferred food. Herbicides and pesticides are not readily available, so one objective was to determine the best time of planting cowpea to avoid disease and pest problems. Another objective was to determine the best crop geometry (between- rows, within rows, alternate rows of cereal and cowpea, double rows of cereal and cowpea) for intercropping. Preliminary results indicate that planting cowpea either between or within the rows of maize has little effect on maize yield, but cowpea planted between the rows flowers sooner while cowpea planted within the rows is easier to cultivate, weed and harvest. The 30 Women's Societies growing maize and cowpea this year are being encouraged to save the cowpea hay as well as the maize stover as feed for their small ruminants.
The Stylosanthes species that are adapted to The Gambia are prolific seeders and have invaded many other research plots. This ability to colonise the low-fertility, slightly acid soils may be an advantage. Farmers generally do not practice crop rotations, although they are aware that they should. The presence of stylosanthes in fields that are under continuous cereal cropping may improve the fertility of the soil as well as providing a source of feed in the dry season. A trial on undersowing maize with S. scabra, S. humility and S. hamata is being conducted at Yundum, Sapu, YBK and one village site to investigate the potential of this system.
Since previous attempts at alley cropping have been unsuccessful, it is too early to say what the results of the 1985 alley cropping experiments will be.
Feeding and grazing trials
Results of the feeding trials have been published (Hedrick and Boding, 1983). It was found that animals could maintain weight over the dry season on crop residues of fairly low nutritive value. Table 2 shows the nutritive values of crop residues used in The Gambia. Groundnut hay is underutilised, and is often left in the field or sold to
Senagalese traders. A small amount is saved by farmers for their draught animals (oxen, donkeys, horses) but with 95% of the farmers raising groundnuts (Dunsmore et al, 1976) and many starving animals, clearly a major extension effort is needed on the management and use of groundnut hay and other crop residues.
Table 2. Crude protein, crude fibre and ash contents of some commonly available crop residues in The Gambia.
|
Feedstuff |
Crude protein |
Crude fibre |
Ash |
|
(%) |
(%) |
(%) |
|
|
Groundnut hay |
11.9 |
24.4 |
6.3 |
|
Rice straw |
4.4 |
28.2 |
20.8 |
|
Gamba grass hay |
4.0 |
36.5 |
4.5 |
|
Maize stover |
3.1 |
37.1 |
4.5 |
|
Sorghum stover |
1.7 |
33.9 |
6.2 |
|
Maize silage |
3.5 |
32.0 |
6.0 |
|
Sorghum silage |
4.4 |
27.8 |
6.6 |
Grazing trials were conducted at Yundum, Sapu and YBK from February through December 1984. The two most preferred species of legumes were S. hamata and S. humilis. At Sapu, the goats ate most of one plot of 3-month-old leucaena seedlings once: that was the only instance that any of the livestock would eat leucaena.Paradoxically, in March 1985, when cattle were turned into the plots to graze off the standing biomass, they grazed off most of the leucaena at all three sites. The question always arises in preference trials as to whether an unpalatable plant would become palatable were it the only one on offer. Indeed, when the small ruminants were staked in plots of S. scabra they eventually ate that legume. It is as useful to know which species are unpalatable as palatable when considering how to provide dry-season grazing. An unpalatable species such as S. scabra would escape grazing early in the dry season, thus enabling it to reseed and be grazed later in the dry season when bush fallow, for example, has been exhausted.
In the village-level feeding trials, little was done with forage legumes. An attempt has been made to establish fodder banks of stylosanthes and to oversow some rangelands with stylos, but as yet this provides only a very small proportion of the feed offered to the village herds.
Constraints
The land-tenure system and poor seed availability are important constraints on the establishment of a viable forage legume component in Gambian farming systems.
Land around villages is allocated to individuals by the chief each year, and generally there is no assurance that an individual will receive the same piece of land every year. Hence, there is little incentive to improve the land through manuring, mulching, fencing or crop rotation. Grazing animals are allowed free access to all lands. Thus, there is no incentive for a farmer to plant a forage crop, since all the animals of the village would have free access to it.
Nevertheless, small steps have been taken towards developing feed resources at the village level through the deferred-grazing programme. Areas of 10-20 ha have been fenced, protected from grazing and partly improved. Farmers can see the sharp contrast between fenced and unfenced areas. One village has even tried to defer grazing on some of their rangeland without fencing and has been partly successful because the village is in a very remote part of the country. Whether this can be extended remains doubtful; an isolated village or one with a strong chief could enforce the deferred grazing and/or the establishment of fodder banks, but until title and ownership of land is a legal reality throughout the country, it will be very difficult to progress with development of pastures.
The second important constraint is lack of forage-legume seeds. The approach to this problem has been three-fold. Due to the necessity of producing results as quickly as possible, work has progressed using the dual-purpose legumes already grown in The Gambia, cowpea and groundnuts. While research continues on these crops, a major extension effort is needed to instruct farmers in their use as livestock feed. The second step has been to continue research on leucaena because of its excellent seed production. The third step has been to train two Gambians in seed production and to start a small seed multiplication unit for forage legumes, primarily stylosanthes.
Livestock production in The Gambia at present is a very low-input, low-output system. Cattle are not primarily raised for sale, and farmers are interested mainly in maintenance rather than production. Cattle are herded mostly by Fula, who are paid in milk, thus involving no capital outlay by the farmer. Most farmers would like to increase their herd size, but not their outlay on livestock production.
Thus, there is little scope or incentive for increasing livestock production. However, the late start of the rains in 1985 led to the death of large numbers of livestock in The Gambia, which emphasises the need for greater feed resources. Due to the land-tenure system, farmers are reluctant to plant forage crops. While the use of cultivated pastures is not likely to be adopted in the near future, and may never have a place in Gambian farming systems, cultivated fallows and intercropping legumes with cereals should be encouraged to provide the additional feed necessary. Introducing forage legumes into the farming systems should also have the additional benefit of increasing soil fertility, thereby increasing cereal yields. Several forage legumes have been identified that are adapted to Gambian conditions and that may be useful in a number of systems. Efforts should be made to introduce systems that include a forage legume component.
Acknowledgements
The author wishes to acknowledge the efforts and assistance of the Forage Agronomy Unit (Bambo Ceesay, Kutubo Sanyang, Lamin Jobe) and the Range Ecology Unit (Scotty Sefendol and Alieu Joof).
Dunsmore J R. Blair Rains A, Lowe G D N. Moffat D J. Anderson I P and Williams J B. 1976. The agricultural development of the Gambia: An agricultural, environmental and socioeconomic analysis. Land Resource Study 22. Land Resource Division, Ministry of Overseas Development, Surbiton, Surrey, England. 450 pp.
Hedrick D and Bojang M. 1983. Final report of the forage agronomist, Mixed Farming Project. Technical Report No. 2. MANR/GOTG/CID/CSU/USAID. 45 pp.
