Rethinking Agriculture for New Opportunities 415enhanced as soil organic matter content increases. Research shows the benefits of
utilizing organic means to maintain soil fertility and also of adding some inorganic
nutrients in combination with organic inputs to get the best results.^15
Adding appropriate amounts and combinations of chemical nutrients can
increase both plant productivity and the amount of crop residues (shoots and
roots) that become available to increase and maintain soil organic matter. Aug-
menting organic matter is especially necessary in tropical soils, which, due to cli-
matic and edaphic conditions, are more likely to need maintenance and restoration
of organic material and nutrients. The bottom line is that chemical fertilizers by
themselves are no substitute for incorporation of soil organic matter. Ideally both
will be used in synergistic ways.^16
Irrigation is not the only way to deal with water limitations
A mechanistic conception of agriculture reinforces the millennia-old fixation on
irrigation as the best if not the only means of providing water for plants in water-
scarce environments. In many places, given hydrological cycles and opportunities,
irrigation is certainly necessary for the practice of agriculture. But its success over
several thousand years has led people to look to this technology as the universal
solution to water scarcity problems. When crops need water, the first thought is
how to provide irrigation from surface or groundwater sources.
But there are other ways to meet crop requirements besides capturing water in
a reservoir, by river diversion or by pumping it from some body of water above or
below ground, and then conveying it through canals and other structures to deliver
it to particular fields, in amounts and at times when it is needed.^17 In much the
same way that assuming soil fertility problems are best solved by fertilizer applica-
tions, seeing water shortages as best handled by irrigation has made water harvest-
ing and conservation almost lost arts. When farmers in semi-arid Burkina Faso,
assisted by OXFAM, demonstrated that they could grow much better millet crops
simply by placing rows of stones across their fields, to slow water runoff and store
it in the soil, this was seen as a remarkable technology (Harrison, 1987, pp165–
170); numerous case studies with similar results have been documented in Reij
et al (1996). Such practices should become part of the repertoire of soil and water
management practices that farmers can adopt to utilize available rainfall most
advantageously. Using mulch to capture water and slow evaporation is another
simple method.
Measures to conserve and utilize water, like planting crops in certain rota-
tions or seeding a new crop in a standing one to capitalize on residual moisture,
should not be seen as something novel but rather as something normal, making
the best use of water in combination with soil. Methods including collecting and
storing water in small catchment dams, large clay jars or simply in porous soils
should be experimented with to determine which designs can provide enough
water to crops and animals (and for human uses) to justify the expenditure of
labour and capital and sometimes land. Small catchment ponds are becoming