The rediscovery of traditional agriculture
AGRICULTURAL scientists have recentlybegun to recognize that many farming systems that have persisted for millennia exemplify careful management of soil, water, and nutrients, precisely the methods required to make high-input farming practices sustainable. This overdue reappraisal stems in part from the need to use inputs more efficiently, and in part from the growing interest in biological technologies.
Traditional farming systems face realagronomic limits, and can rarely compete tonne for harvested tonne with high-input modern methods. It is important to recognize these limitations, for they determine both how traditional practices can be modified and what such practices can contribute to the effort to raise agricultural productivity.
First, most traditional crop varieties havelimited genetic potential for high grain yields. They are often large-leaved and tall, for example. These traits help farmers meet non-food needs, supplying thatch, fuel and fodder as well as food to farm households. Traditional varieties respond poorly to the two elements of agronomic management that make high grain yields possible: dense planting and artificial fertilizer. Despite these limitations, traditional varieties also contain genetic diversity that is invaluable to breeders in search of genes for disease- and pest-resistance and for other traits.
Second, peasant farmers often have toplant in soils with serious nutrient deficiencies, where crop combinations and rotations are needed to help offset the limitations. Many tropical soils, for instance, lack sufficient nitrogen to sustain a robust crop. Soils in vast areas of semi-arid Africa are deficient in phosphorus. High-yielding varieties, more efficient in converting available nutrients into edible grain, can rapidly deplete soil nutrients if they are planted by peasant farmers who cannot purchase supplemental fertilizers.
Nonetheless, traditional methods can makean important contribution to efforts to raise agricultural productivity. They offer what have been called "principles of permanence'. "Neither modern Western agriculture nor indigenous traditional agriculture, in their present forms, are exactly what will be needed by most small-scale farmers,' says one researcher, Gerald Marten of the East-West Center in Hawaii. "The challenge for agricultural research is to improve agriculture in ways that retain the strengths of traditional agriculture while meeting the needs of changing times.'
Intercropping, agroforestry, shifting cultivation,and other traditional farming methods mimic natural ecological processes, and the sustainability of many traditional practices lies in the ecological models they follow. This use of natural analogies suggests principles for the design of agricultural systems to make the most of sunlight, soil nutrients and rainfall. …