Previous - Next
Land husbandry: a new philosophy
Land husbandry: a strategy for action
Land husbandry: a new philosophy
Runoff and erosion control has proven more complex than anticipated. On the one hand, there are many processes of soil degradation, and there is a long way to go before the technology is tailored to the range of environments found in the world: remedies are too often applied with no knowledge of their effectiveness against erosion, their feasibility or their economic viability in a given time and place. Moreover, many sociological and economic factors have not yet been properly grasped: land tenure problems and investment security, farmers' goals and priorities, the availability of land, inputs and labour, and opportunities to get more benefit from farm produce and improve living standards, health, etc.
Simply conserving soil cannot satisfy most farmers because it brings no immediate return for the extra work required. Most land is already so poor and degraded that even if losses through erosion are curbed, the productivity of both land and labour is still mediocre. However, the population doubles every 15 to 30 years, which implies the challenge of doubling production in ten years in order to catch up with the geometric progression in population. Soil conservation is not enough: fertility has to be restored in order to allow a satisfactory and early return on the labour invested. Land husbandry tries to bring about a decided increase in yields, while stabilizing the environment.
In pursuit of this aim, land husbandry improves the management of water, organic matter and nutrients in order to create intensification points for production and for development of the rural environment through animal husbandry (manure being one of the keys to productivity on tropical soils incapable of storing much water or nutrients), agroforestry and off-season crops. Land husbandry aims primarily at a significant increase in yields (or, better, in net income), and this requires stabilization of the environment. Erosion control is no longer the rallying call for public opinion, but simply one necessary component of a technological package.
The belief was that soil nutrients could be mobilized through various biological means manure, compost, mulch, hedges, green manure. Many recent examples from tropical countries have shown that on acid ferralitic soils agroforestry (and particularly cropping between hedges) can halt erosion even on steep slopes (25 to 60%) and curb the degradation of cultivated land. However, like green manuring, this "simultaneous cultivation and fallow" immobilizes 10 to 20% of the land simply in order to maintain a very modest level of production, not enough to keep pace with population pressure. If this vicious circle is to be broken, soil fertility must first be restored which is not possible without massive applications of manure (3 to 10 t/ha), lime (1 to 5 t/ha) and mineral fertilizers that can be directly taken up by crops.
The densest rural populations in the world live in multi-storey gardens where positive interaction between livestock, crops and trees is pursued to the furthest extreme. In Africa there is still a great deal to be done in order to intensify animal husbandry and manage trees so as to minimize competition with traditional crops.
Land husbandry: a strategy for action
This work has collated research on the dynamics of erosion and the erosion control methods developed over the past forty years, especially in French-speaking Africa, and has led to the formulation of new research approaches and orientations for rural development.
NEW RESEARCH APPROACHES
• Study of traditional strategies for managing water, soil and soil fertility: the way they work, the causes of their decline, and the possibilities of improving them;
• study of the feasibility, acceptability, effectiveness and economic viability of erosion control methods;
• study of the costs of erosion and of erosion control at the individual plot and watershed levels;
• regional adaptation of methods of managing water, nutrients and biomass;
• refining methods of dissipating runoff energy on slopes;
• the social and economic aspects of erosion, and how to increase farmers' awareness of problems of environmental degradation;
• degradation and, above all, restoration of the productivity of the land: the roles of livestock, trees, micro-organisms (manure) and mineral supplements;
• development of models of the risks of runoff, drainage and erosion, but also optimal land use, taking account of the limitations imposed by production systems and farm sizes.
NEW ORIENTATIONS FOR RURAL DEVELOPMENT
Since the participation of farmers is vital for the sustainability of erosion control, farmer priorities must be taken into account, and research involve their participation in finding ways of improving land productivity and getting a better return on their labour. Erosion control should no longer be presented as the main objective, but as part of a technological package designed to improve the management of water, biomass and nutrients:
• systematically improving existing techniques while avoiding increased dependency on inputs coming from outside the village (funding, sophisticated technology, etc.);
• integrating new elements into farming systems (agroforestry, multicropping, catch fallows of legumes, accelerated rotation, supplementary irrigation and manuring);
• promoting the cheapest and most effective erosion control structures;
• taking account of market studies and the condition of the road network in order to draw the most benefit from production;
• refining methods of draining both roads and the slopes on which they are built;
• adaptation of erosion control to the land-tenure system.
The prospects for research and rural development outlined in this book call on the various parties to work together. The various activities are envisaged within a framework of close cooperation between national agencies, non-governmental organizations, development agencies and the users of the land. The role of national agencies in particular should be transformed from that of executing agency to that of promoter. The ideal programme directly involves the users of the land in planning and implementing their own solutions. To this end, national agencies should assume responsibility for creating an awareness of land degradation, and the users of the land should be helped to develop their own organizations.