Food for All - Agri-culture: Reconnecting People, Land and Nature - page 86

Sustainable agriculture starts with the soil by seeking to reduce soil
erosion and to make improvements to soil physical structure, organic
matter content, water-holding capacity and nutrient balances. Soil health
is improved through the use of legumes, green manures and cover crops;
the incorporation of plants with the capacity to release phosphate from
the soil into rotations; the use of composts and animal manures; the
adoption of zero-tillage ; and the use of inorganic fertilizers where needed. 14
Some of these are age-old practices adapted for today's conditions. Some,
though, seem to break one of the fundamental rules of agriculture. Ever
since the birth of farming some 12,000 years ago, farmers have been
ploughing, or tilling, the soil. Yet, in the past decade, Latin American
farmers have found that eliminating tillage can be highly beneficial, and
many in Africa have adopted no-till or only shallow cultivations for rice
production. At first sight, it seems a strange idea. After harvest, the crop
residues are left on the surface to protect against erosion. At planting, seed
is slotted into a groove that is cut into the soil. Weeds are controlled with
herbicides or cover crops. This means that the soil surface is always
covered, and the soil itself no longer inverted.
The fastest uptake of these minimum till systems has been in Brazil,
where there are some 15 million hectares under plantio direto (also called
zero-tillage even though there is some disturbance of the soil), mostly in
three southern states of Santa Caterina, Rio Grande do Sul and Paraná,
and in the central Cerrado. In neighbouring Argentina, there are more than
11 million hectares under zero-tillage, up from less than 100,000 hectares
in 1990, and in Paraguay there are another 1 million hectares of zero-
tillage. 15 There are several million hectares of conservation or no-till
farming in the US, Canada and Australia; but here it mostly tends to be
simplified modern agriculture systems, which save on soil erosion but do
not necessarily make the best use of agroecological principles for nutrient,
weed and pest management.
In Argentina, Roberto Peiretti is responsible for technical and manage-
ment decisions on about 10,000 hectares of farmland in Córdoba
Province. He is chairman of the Argentinian no-till farmers' organization
and is an enthusiast. He says:
We were faced with serious soil deterioration, and knew we needed to find a different
way to produce. . . applying no till as an entirely holistic approach enabled us to
discover an entirely new scenery, a system based on understanding and emulating
nature as much as possible.
Their approach has been to establish no-till research and extension groups,
and to link these to regional and national levels. These coalitions have been