Alternatives to slash-and-burn
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CTA. 1995. Alternatives to slash-and-burn. Spore 59. CTA, Wageningen, The Netherlands.
Permanent link to cite or share this item: http://hdl.handle.net/10568/47143
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Estimates indicate that more than 200 million landless people have migrated into tropical forests in recent decades, and that these numbers are increasing. Farmers who cultivate the land can no longer give it time to fully recover; fallow periods...
Estimates indicate that more than 200 million landless people have migrated into tropical forests in recent decades, and that these numbers are increasing. Farmers who cultivate the land can no longer give it time to fully recover; fallow periods are shortened to five years or less and forests cannot regenerate. Nutrients and organic matter in the soil are depleted and crop yields steadily decrease. But population pressures and shortage of fertile land often combine to trap resource-poor people into a vicious circle of slashing and burning more forest and bush. Slash-and-burn agriculture is now associated with destruction and depletion of soils, but that was not always the case. In fact for thousands of years, wherever agriculture was practiced, it was the most usual form of farming. Farmers lived by clearing small areas of trees, burning them and planting crops into the ash-enriched soil. Then, when the fertility of the ash from the felled forest vegetation was exhausted, the early farmers moved on to clear another portion of forest, leaving their abandoned farm land to revert to scrub and eventually to full forest. However, these days there are too many people, not enough forest, not enough time for vegetation to grow back and not enough time for soil fertility to recover. The problem has been recognized for a long time. With each passing year, thousands more hectares of depleted soils pass out of useful production. With no other option, people turn to, and encroach upon, the remaining but fast-dwindling tropical forests. The result is deforestation which increases water run-off, causes severe soil erosion, loss of fertility and loss of biodiversity. In February 1992 the United Nations Development Programme (UNDP) sponsored the First Global Workshop on Alternatives to Slash-and-Burn. The Alternatives to Slash-and-Burn Initiative (ASB) was created. The 10-year initiative involves a total of 18 national programmes, international research centres and NGOs, and is being coordinated by the International Centre for Research in Agroforestry (ICRAF) in Kenya. Avoiding soil depletion The Initiative has many long and short term goals to be implemented at all different levels, from donors, governments, institutions and NGOs to extension services and farmers. But admirable as these goals are, the practitioners of slash-and-burn (the farmers) are trying to survive - are there any practical alternatives for them? Dr Pedro Sanchez, Director General of ICRAF, believes there are. He maintains that when land has been cleared by slash-and-burn for food crops such as rice, maize or beans, trees should be planted at the same time, particularly fast growing leguminous varieties to improve the fertility of the soil. In this way the soil is given a good start to develop soil-protecting and nutrient-enriching cover before the land is returned to fallow. Later, although the land may not be able to support food crops for a period of time, the planted trees can continue to provide an income in the form of forage, timber, fruit and possibly even medicinal products. This diversity of land use then becomes, in effect, a managed fallow as opposed to a traditional bush fallow. Another technique is to grow living fences. Where land has been cleared to provide pasture for cattle there are two ways in which the forest becomes depleted. The first is the clearing of trees to provide the land area for pasture, the second is the cutting of timber to provide fence posts. Farmers should be encouraged to plant living fences of fast-growing leguminous trees to which fencing wire can be attached; this serves the double purpose of containment and provides browse for the cattle at the same time. The trees also protect and enrich the soil. Such alternatives go a long way to help reclaim vast tracts of degraded land and reduce pressure on remaining forests. Overlooked and undervalued Indigenous trees are not only greatly valued by forest dwellers for the fruit, medicine, fuelwood, fodder, building materials and shade that they provide but these forest products are also appreciated by neighbouring farmers. Yet many species of these indigenous trees are not used to their full potential, either because they are not known or because they are 'wild'. In the past many have been ignored by modern researchers as unimportant but they are now beginning to receive more attention. Dr Roger Leakey, Director of Research at ICRAF, refers to them es 'Cinderella' trees. These Cinderella species can be improved through the processes of domestication, selection and breeding that have been applied so successfully to agricultural and horticultural crops. One of the first groups of Cinderella species that could be improved is indigenous fruit trees. Several fruit species are emerging as economic options for putting money into farmers' pockets. Indigenous species, such as the bush mango (Irvingia gabonensis) in the humid lowlands of West Africa command a ready market. In the dry, savannah-like 'miombo' ecosystem of southern Africa more than 50 species of indigenous tree bear edible fruits which provide local people with reserves of food during seasonal shortages and famine. In Malawi, a SADC-ICRAF research project collected seed of 18 fruit tree species with the aim of developing propagation techniques, using the seed and vegetative parts of the native fruits trees. Sufficient planting stock was raised to allow assessment of growth and fruit yield from these multipurpose trees after planting in the field. The survival rate was excellent (85-100%) despite one of the worst droughts of the century in 1991-92. One particular species, wild medlar (Vangueria infausata), fruited particularly well: 2.5-5kg of fruit per tree per year with fruits up to 10 times bigger than fruits produced by trees in the wild, and local farmers in the Makoka district in Malawi became very enthusiastic about planting the tree. New ways of managing slash-and-burn and development of Cinderella species are not by themselves going to solve the problems of shortages of fertile land. Many other factors have to be taken into account. Governments need to formulate policies that provide security of land tenure and access to markets, and policies which encourage participation of small-scale farmers, particularly women and women's groups, in the decision-making processes. Only then will rural people feel that it is to their economic advantage to employ sustainable farming methods which not only ensure their own survival, but which also provide for the future of their children and the environment.
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