In the past, soil conservation was synonymous with preventing soil erosion. Measures to control soil erosion were handled in isolation from other aspects of land use. A more recent approach integrates soil management with productive land use and the maintenance of soil fertility through appropriate combinations of crops and livestock.
Improved systems of crop/livestock integration in the uplands are based on two key principles.
Farm families are finding it increasingly difficult to earn a livelihood from slopeland agriculture because of stagnating yields, the increased cost of inputs, adverse and disorganized markets, and growing population pressure. However, Asian scientists are working to help improve slopeland agriculture in the region.
Farmers tend to integrate livestock and crop production better than most scientists do! Traditional systems already combine various mixtures of livestock species and crops. The challenge is to increase the productivity of traditional systems, so they produce a higher usable biomass while conserving the natural resources on which the whole agricultural system depends.
Crop-livestock integration increases the overall productivity of ecosystems, since livestock can use otherwise unusable parts of plants and crop by-products. Conversely, crops can utilize the livestock manure as a source of plant nutrients. Crop-livestock integration also increases sustainability. It is the flow of energy and materials that determine the stability of slopeland ecosystems. Closed systems in which nutrients and energy are recycled are much more sustainable than an open system which leaks nutrients, and which needs higher inputs to maintain its productivity in the long term.
The most productive ecosystems are multi-layered and diverse. It is this type of ecosystem which produces the highest biomass, and does most to conserve soil and water resources. Most of the models incorporate perennial crops, either for cash or for forage. Leguminous trees and shrubs were particularly important. They can be used as a source of livestock feed, and can also fix atmospheric nitrogen and thus increase soil fertility.
In traditional slopeland farming systems, cattle and goats are often taken up onto higher ground away from cropland during the wet season, or left to graze in the forest. After harvesting, the animals are brought back to the village to graze on the fallow croplands over the dry season. Although farmers in principle are using separate zones for crops and livestock over the growing season, in practice there is often competition between the two. Grazing animals sometimes damage crops, and farmers may have to put a lot of time and effort into protecting their crops with fences.
Cut-and-carry livestock production systems are well suited to Asia's intensive farming. In the Sloping Agricultural Land Technology (SALT) system, developed in the Philippines, goats or other small livestock are fed on nitrogen-fixing legumes grown in a forage garden, usually together with food and cash crops. Leaves and branches of high-protein species such as
Desmodium rensonii, Gliricidia septum, Indigofera tyesmani and
Leucaena leucocephala are cut periodically and used as livestock feed for penned animals. This system gives more efficient land use and higher milk production than free-ranging animals. The fact that the animals are penned also makes handling easier, and allows the farmer to closely monitor the health and breeding cycles of his livestock. Pens also ensure that livestock manure is deposited in a limited area, so it can be collected to use as fertilizer.
Disadvantages include the heavy labor demand, the possibility of infectious diseases among penned animals, and possible adverse effects when high levels of some legume shrubs are used as feed. For example, some leucaena leaves have a high mimosine content, which can cause hair loss and poor performance in swine. Other species of leguminous shrub can sometimes cause bloat in sheep and cattle. While cut-and-carry livestock systems are more intensive and potentially much more productive than free grazing, farmers need to apply a higher level of management and different skills.
The traditional system of crop production on slopelands in tropical Asia is slash and burn, in which forest is cut and burned for the production of annual food crops. The cleared land is abandoned after a few years, and the group moves on to clear new land. In the past, when populations and land clearings were both small, the forest could be allowed to regenerate for thirty years or more, giving a sustainable cycle. As population pressure has risen, however, cultivators are clearing larger areas of land, and leaving short fallows of only a few years. As a result, yields are falling, putting even more pressure on available land.
Weeds are a major constraint. Slash and burn farmers nearly always rely on manual rather than chemical weed control, and shorter fallows mean more weeds. One program described at the Workshop is controlling weeds by improving the quality of the fallow. One solution is the accelerated fallow, using legumes and integrated livestock production. Another solution is the extended fallow, based on perennial cash crops. This also often integrates livestock into the production system, using trees such as paper mulberry as forage. Rotations with improved fallows may help to overcome the serious weed problems, while livestock will benefit from access to high-quality feed resources.
An important new development is participatory approaches to technology development (PTD). The process of PTD begins with a meeting of researchers and farmers, where farmers identify their main problems, give them a priority, and describe what they have done in the past to solve them. Researchers then bring to farmers useful information, planting materials etc. which they think will benefit farmers. Farmers test these for themselves in whatever way they prefer. When they develop promising technologies, scientific experiments may be carried out to validate the farmers' experience. Once farmers are testing technologies, there follows a period of evaluation in which farmers describe what technologies they like and why they like them, and what features need to be improved. Evaluation identifies, not only promising technologies, but also the criteria being used by farmers to judge whether a technology is successful or not.
"The key principle of PTD is active, decision-making involvement of farmers at all stages of the technology development process"
(From FFTC Extension Bulletin No. 462 on this database).
The integration of crops and livestock is a promising agricultural system for low-income small-scale farmers. A great advantage of crop-livestock integration is that it uses diverse resources such as fodder legumes, crop residues and livestock manure in a system of nutrient recycling. Livestock provide a high level of profit per unit of labor input, plus valuable manure for use as fertilizer. Livestock also have the great advantage of being relatively easy to market compared to harvested crops. There is a steady demand for livestock products, with relatively high and stable prices.
Another great advantage of livestock production in slopeland agriculture is that the animals can walk to market. This is a considerable benefit in remote areas with poor roads, where farmers would otherwise find it very difficult to market what they produce. In such areas, livestock may be the only feasible source of cash income.
The way forward seems to be highly productive mixtures of species, including a range of complementary crops at different levels in the canopy, and forage species as livestock feed. At present, many systems of crop/livestock integration are based on the use of separate zones during the cropping system, and free grazing in fallow fields during the off season. Such systems are already giving rise to conflict, and damage of crops by livestock. Such conflict is likely to intensify as populations become even denser and the cropping period is extended. They will probably be replaced by cut-and-carry livestock systems based on crops of nitrogen-fixing legumes and high-yielding improved grasses.
Similarly, slash and burn agriculture is undergoing a transition to sedentary cultivation. For unimproved systems, this is a process of impoverishment, with progressively lower yields and worsening weed and erosion problems. However, the Workshop presented a number of hopeful examples of how this downward spiral can be halted and reversed with appropriate cultivation methods based on complementary crop and livestock species. These were not only described during the paper presentations, but actually viewed during the field trip.
Livestock can also be integrated into slopeland reforestation programs, particularly in the early stages of tree growth. New systems of research and extension based on PTD are helping ensure that technology is more appropriate to farmers' needs, and that it solves those problems which are seen as crucial by the slopeland farmers themselves.
Location: Ho Chi Minh City, Vietnam
Date: November 16-19
No. Participating Countries: 7 (Japan, Lao PDR, Philippines, Sweden, Taiwan ROC, Thailand, Vietnam)
No. Papers: 11
No. Participants: 45 plus observers
Co-sponsor: University of Agriculture and Forestry at Thu Duc, National Universities of Ho Chi Minh City, Vietnam
1. Ecological concerns in crop-livestock integration with slopeland
- Percy Sajise
2. Combination use of native and improved pasture for beef production in Southern Japan: A case study
- Yoshito Yamamoto
3. Dynamics of crop-livestock integration in slopeland areas
- Edwin C. Villar
4. Integration of forest-livestock management in Taiwan
- Kuen-Jaw Chen
5. Social science research in upland crop-livestock integration system
- Peter Horne
6. The state of the art of crop-livestock production in the slopelands of Lao PDR
- Vanthong Phengvicith
7. Nitrogen fixing cut-and-carry forage systems for small farmers in Asia's uplands
- Jeff Palmer
8. Participation scheme of small holder dairy farmers in Northeast Thailand on improving feeding systems
- Metha Wanapat
9. Trees and livestock to stabilize upland rice shifting cultivation systems in Northern Laos
- Keith Fahrney
10. Improving land use and livestock productivity in slopeland areas
- Duong Duy Dong
11. Improving biomass productivity of plants, soil fertility on sloping land and farm household incomes in the Bavi mountainous area of Vietnam
- Nguyen Thi Mui
Figure 1 Salt Technology: Low-Cost Housing for Cattle
Figure 2 Salt Technology: Low-Cost Housing for Goats
Figure 3 Milking Goats on a Salt Farm
Figure 4 a Salt Field, Combining Subsistance and Cash Crops with Hedgerows of Forage Legume Species.