FAO calls for minimum tillage to halt soil erosion


Ploughing can be bad for the soil. A minority of agriculturalists have been saying so for years and FAO is now adding its voice to the call for a drastic reduction in tillage in order to slow land degradation around the world.

Both mechanized and animal tillage can lead to soil loss

According to the Organization, "with the advent of tractors, the tendency was to increase tillage and farmers started to believe that the more you till the soil, the more yield you get. The truth is that more tillage causes more erosion and soil degradation, especially in warmer areas where the topsoil layer is thinner." Today's conventional ploughing methods cause severe soil loss and desertification in many developing countries. FAO estimates that some 40 percent of land degradation around the world is caused by soil erosion.

The Organization has issued a dramatic warning to farmers: "Parts of Latin America and Africa could become dust-bowls if farmers don't change their tillage practices. Every time a farmer tills land to control weeds, the soil becomes more vulnerable to erosion and the soil structure is destroyed. Conventional tillage with tractors and ploughs provokes soil compaction and biological degradation. Even animal traction systems, to a lesser extent, can lead to erosion. The way soils are cultivated today needs to be drastically changed."

FAO is holding a workshop to promote conservation tillage in Harare, Zimbabwe, from 22 to 27 June. The meeting will begin work on the formulation of a code of conduct on soil management and the outline of a regional project on conservation tillage will be prepared. The German Agency for Technical Cooperation (GTZ), the South African Research Council, a Swedish-funded FAO project and the Zimbabwe Farmers Union will participate in the meeting.

In Latin America, RELACO, a network promoting conservation tillage, was established in 1992 and more than 14 million hectares of farmland in the region are now under zero-tillage - in which the soil is disturbed only where the seed is planted. One of the tools specially designed for this is the chisel plough.

In Africa, minimum tillage is mainly practised only on large estates, but the regional project will be targeting smallholders too. Significantly for smaller farmers, minimum tillage also cuts the costs of land preparation. For example, production costs per acre for soybeans could be cut by US$27 in Argentina, US$14 in the United States and US$11 in Brazil, by introducing minimum tillage techniques.

According to FAO expert José Benites of the Soil Resources Management and Conservation Service, soils in tropical countries do not normally need to be tilled. "The most desirable form of tillage is conservation tillage which leaves a protective blanket of leaves, stems and stalks from the previous crop on the surface. This cover shields the soil surface from heat, wind and rain, keeps the soil cooler and reduces moisture loss by evaporation."

Go to interview with Theodor Friedrich, FAO Agricultural Engineer

22 June 1998

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