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ALTHOUGH SOME TRADITIONAL SOCIETIES PRACTISED SOIL CONSERVATION SUCCESSFULLY, MANY RECENT ATTEMPTS TO HALT LAND DEGRADATION HAVE TURNED OUT TO BE COSTLY FAILURES
Although traditional systems of land use rarely led to rapid land degradation, problems did arise in some of the more fragile areas where large numbers of people were concentrated. Farmers often responded with sophisticated and effective conservation measures that were developed to overcome degradation threats, and to maintain or raise crop and livestock yields.
In southern Ethiopia, for example, the Konso people live in a steep, erodible area subject to unreliable rainfall. Over the years, the Konso have terraced most of their land and developed a complex system of agroforestry and water harvesting. Compost and manure are spread on the fields to maintain soil fertility, while cattle are stall fed. This system (see box below) appears to have worked well until recent times when population numbers became too great for the available land.
Another example of a traditional conservation system existed in the semi-arid areas of southern Burkina Faso and in neighbouring areas of Ghana. There the Birifor people developed a system which includes the use of stone ridges along the contour, small earth dams, the diversion of run-off water, the- use of manure and compost, and cultivation on mounds. This system minimized land degradation and at the same time maintained soil fertility and crop and livestock yields.
Systems such as these have two things in common: they are adapted to their own environmental conditions; and their primary aim is to maintain soil fertility and agricultural yields at a satisfactory level - the prevention of land degradation was seen simply as a desirable side effect.
Conservation in the recent past
Neither traditional systems of using the land, nor the responses of traditional societies to increasingly severe pressures on the land, have been able to cope with the rapid growth of population in Africa for most of this century. Many of Africa's colonial administrations, however, undertook large-scale programmes intended to halt or reduce high rates of erosion.
Typical of these was one launched in Lesotho in the mid-1930s. Over the following 30 years some 400 000 ha of land - virtually all the cultivable land of this small country - was treated: contour banks were built, grassed strips established to halt erosion, small dams erected in the water courses, trees planted in gullies and excessive run-off diverted from cultivated fields. Disappointingly, these achievements have not been maintained by the farmers, who had come to see maintenance as a government responsibility.
The programme Lesotho was typical of many of the large-scale, costly projects of that time. In spite of these efforts, the battle was not won. Vast areas of Africa continued to be eroded and the degradation of the semi-arid region became so serious that a new word, desertification, was coined to describe the gravity of the situation.
Few African governments can afford to repeat the expense of these large-scale programmes of the past. Indeed, many governments appear disheartened by the relatively poor results that past programmes have achieved. It is therefore important to ask why these programmes were not more successful.
What went wrong
The science of land conservation has existed for little more than 50 years. Over this period attempts to control land degradation have been directed mainly at preventing or reducing soil loss. Soil erosion was seen as a physical process, to be controlled mainly by physical measures; it was not recognized as the consequence of the more fundamental problems of incorrect land management and lack of vegetative cover.
Usually, the problem was identified only after the situation had become serious - a new dam had filled with silt, a bridge washed away or a road cut by gullies. By this time, large quantities of topsoil had already been lost and the productivity of the land seriously impaired. Even though the more important issue was loss of productivity, the problem was usually seen as one of soil loss producing physical damage downstream to rivers and reservoirs.
Physical measures designed to prevent or slow down the process of soil loss would then be considered. Plans would be produced which, if properly implemented and maintained, would greatly reduce the rate of land degradation.
The Konso: a traditional solution The Konso of southwest Ethiopia have developed a complex and sophisticated form of agriculture which has allowed them to subsist in a mountainous area with fragile soils and an irregular rainfall which averages less than 900 mm annually. Their farming is based on an elaborate system of terracing, a variety of soil and water management practices, and the integration of livestock and forestry with the rest of their agriculture. Their terraces are built with stone walls to hold the soil in place and protect it from erosion until the crop roots are sufficiently established to take over. The terraces are often irrigated from collecting basins and by diverting runoff water from paths and roads. On flatter land, the fields are formed into basins with rectangular ridges on an approximate 2 x 4 metre grid. Crop stubble covers the ridges as a protection measure while crops are planted in the basins where water accumulates. The cabbage tree (Moringa stenopetala), from which young green leaves are collected as a vegetable, is planted together with fruit trees in the cropped fields, with increasing densities on the wetter sites. On steeper slopes, terrace walls are made from double layers of rock, and the space between them is filled with soil and planted with leguminous crops. A variety of annuals and perennials is sown in staggered or relay-cropping sequences, usually with sorghum, finger millet or maize as the main crop, mixed with beans, peas, lentils, fruit trees, medicinal species, spices, oil seeds, firewood and building-timber species, root crops and cash crops such as cotton and coffee. Many different species and cultivars are maintained, especially of sorghum, of which more than 23 cultivars have been selected for specific uses, both for tolerance to a range of soil and moisture conditions as well as a range of uses such as baking flour, beer and animal fodder. The latter is particularly important to the Konso, who live in stockaded villages and practice stall feeding of cattle for milk production. The villages contain large reserves of cactus (Opuntia), partly as a standing fodder reserve and partly as a firebreak. Stall feeding permits manuring of the land closest to the village. The fields far from the village receive little manure but are placed under rotations which include fallow periods. The agriculture practiced by the Konso is essentially for subsistence. Few, if any, cattle are sold as markets are too distant. Over many generations the Konso have thus developed an elaborate conservation system which includes:
Elaborate terracing systems developed by the Konso are backed up by extensive manuring, mulching and fallow practices
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Most of these plans depended heavily on the construction of bench terraces, contour banks, check dams and similar works. The problems were treated from an engineering perspective; the planners seldom paid much attention to incorrect land management and use, of which surface run-off and soil loss were only the symptoms. Rarely was there any direct contact between the farmer and the planner.
Plans developed in this way hardly took into account the effects they would have on future production or the immediate needs of farmers. They were aimed simply at keeping the soil in place.
A given plan was then explained to the farmers who were encouraged, cajoled, persuaded or even forced to implement it. At this point the problems really began: programmes proceeded more slowly than planned because few farmers had any interest in them or were only prepared to carry out the work if paid to do so. Even fewer were willing to maintain the work unless made to do so.
With land users so marginally involved, it is not surprising in retrospect that these schemes should so often have turned out to be expensive failures. Farmers, pastoralists and those who relied on woodlands and forests for their livelihoods were often regarded as part of the problem, rather than as the potential solution. No attempts were made to analyse the real causes of land misuse, such as land tenure systems, labour shortages and lack of economic incentives, information and advice.
Palm branches stop Moroccan sand dunes: A simple but effective technology has been developed to halt the spread of sand dunes in southern Morocco. In the mid 1970s dunes were encroaching onto cultivated and settled areas, severely limiting plans for agricultural development. In 1980 a four-year UNDP/FAO project started to investigate methods of sand dune stabilization in the southern provinces. It was originally thought that the sand came from the Sahara, but the project proved the sand was blown along the ground from the Atlas mountains in eastern Morocco. It was impossible to stabilize the source of the sand, so its encroachment had to be controlled where it threatened inhabited or cultivated areas. The most effective technique identified was to build palm branch fences of less than a metre high in connecting squares with seven metre sides. Inside these squares the wind was not strong enough to move the sand, and vegetation could be established. Several types of shrubs and trees were tested and bred to improve their resistance to wind and sand. Fourteen villages, seven palm plantations, and many irrigation canals, roads and railways in the area were protected, and substantial areas of land were reclaimed for agricultural use. When the project ended, local staff continued the work, and a permanent base for desertification control was established which will benefit the entire north African and Near East region Palm branches stop Moroccan sand dunes
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Why conservation schemes often fail
