D+C Development and Cooperation (No. 1, January/february 2002, p. 29)

No Tillage to Prevent Soil Degradation

FAO

Intensive land cultivation methods using tractors and ploughs are a major cause of severe soil loss and land degradation in many developing countries, the UN Food and Agriculture Organisation (FAO) said in a statement today. Especially in warmer areas, where the topsoil layer is thin, conventional tillage contributes to soil loss. Land degradation also occurs in industrialised countries due to exaggerated mechanised tillage using powerful heavy machines.

If farmers applied ecologically sound cultivation and the concept of ‘Conservation Agriculture’, millions of hectares of agricultural land could be protected or saved from degradation and erosion, FAO said on the occasion of the opening of the World Congress on Conservation Agriculture, which took place in Madrid/Spain (October 1–5).

“The way soils are cultivated today needs to be changed,” said FAO Assistant Director-General Louise Fresco. “For agriculture to be sustainable, economically attractive and socially acceptable, it must successfully exploit the productive potential of those crop and animal genetic resources which are best adapted to the local environment. This is achieved by effectively and efficiently using available natural resources without depleting them.”

Applying Conservation Agriculture means that farmers drastically reduce tillage and keep a protective soil cover of leaves, stems and stalks from the previous crop. This cover shields the soil surface from heat, wind and rain, keeps the soils cooler and reduces moisture losses by evaporation. Less tillage also means lower fuel and labour costs, and farmers need to spend less on heavy machinery, FAO said. Crop rotation over several seasons is essential to minimise the outbreak of pests and diseases.

Globally, conservation agriculture is currently being practised on about 58 million hectares of land, from the tropics almost to the Arctic Circle: mostly in the United States (around 20 million ha), Brazil (13.5 million ha), Argentina (9.5 million ha), Canada (4 million ha) and Paraguay (800,000 ha). The system has been adapted for grain crops and pulses, and also for sugar cane, vegetables, potatoes, beets, cassava and fruits.

“The message that no-tillage reduces input costs, benefits soil quality and reduces erosion and environmental pollution, is beginning to be embraced by farmers worldwide,” FAO said.

For the farmer, conservation farming is attractive because it reduces production costs, time and labour. Soil tillage is among all farming activities the single most energy consuming and air-polluting operation. By not tilling the soil, farmers can save between 30 and 40 per cent of time, labour and fuel costs compared to conventional cropping. In mechanised systems, investment and maintenance costs for machinery are lower in the long term.

In many areas it has been observed after some years of conservation farming, that natural springs that had disappeared started to flow again, FAO said. Water infiltrates easily on soils under conservation agriculture, increasing the groundwater level, reducing surface runoff and thus soil erosion.

“Conservation Agriculture reaches yields comparable with modern intensive agriculture but in a sustainable way,” FAO stressed. “Yields tend to increase over the years with yield variations decreasing.”

Conservation agriculture is not organic farming, but both could be combined, FAO emphasised. In Conservation Agriculture, farm chemicals, including fertilizer and herbicides are carefully applied. Over the years, however, quantities tend to decline.

FAO has been promoting conservation farming for more than 10 years, particularly in Latin America where Conservation Agriculture has become a success story. In Brazil’s subtropical southern state of Santa Catarina, farmers in the past relied heavily on mineral fertilisers, toxic pesticides and heavy machinery, such as tractors, ploughs and harrows. They tended to grow the same crop – usually maize – from one year to the next. Increasing erosion and declining yields prompted a fresh look at soil management and a steady shift over the past two decades to conservation agriculture, now being applied on 685,000 ha, or more than one-third of the state’s total cropped area.

FAO is expanding the programme to other regions, such as Africa, Central and South Asia. In the countries of the former Soviet Union, conventional agriculture has led to environmental degradation through the use of unsuitable and obsolete heavy farm machinery which urgently needs to be replaced.


D+C Development and Cooperation,
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