Prevent soil erosion by less ploughing, FAO urges
Author: Martin Roberts
"Intensive land cultivation methods using tractors and ploughs are a major cause of severe soil loss and land degradation in many developing countries," a FAO statement said ahead of a week-long conference in Madrid.
"Land degradation also occurs in industrialized countries due to exaggerated mechanised tillage using powerful heavy machines," FAO added.
The ecologically-friendly alternative promoted by FAO, called "conservation agriculture" entails allowing a protective layer of leaves, stems and stalks from the previous crop to build up on top of the soil, by minimal or even zero tillage.
The organic layer keeps the soil cool and prevents moisture from evaporating, as well as shielding it from heat and rain.
In addition to the environmental advantages, conservation agriculture can cut fuel and labour costs for farmers, FAO says, as well as reducing spending on heavy machinery.
FAO said that conservation agriculture, which it has been promoting for 10 years, is currently applied on some 58 million hectares of land worldwide, mostly in the United States (about 20 million ha) and Brazil (13.5 million ha).
SLOW PROGRESS IN SPAIN
FAO Officials said conservation agriculture could also benefit Europe and particularly Spain, which had a relatively high level of soil erosion.
"Changing weather patterns and the greater frequency of rain storms in Europe suggests that something is wrong with the water-retaining capacity of soil," said Theodor Friedrich, a senior agricultural engineer at FAO.
Specialists said conservation agriculture was gaining ground in Spain but implementing it would imply stricter rotation than at present, and farmers would require convincing that it was worthwhile investing in new machinery.
Spanish agriculture of non-irrigated crops is currently biased towards cereals - mostly wheat and barley - which take up about 5.7 million hectares, compared to about one million for sunflowers and about 450,000 ha for legumes.
Wheat and barley also have the advantage that they can be sown in cool, damp ground in late autumn or winter, whereas sunseeds need to be sown in September, when the ground can be hard and dry, which favours traditional tillage.
An official at the Spanish Co-operatives Confederation said farmers had already taken an important step by allowing organic layers to build up after a harvest rather than burning stubble, as they used to.
"It's easy to see results on small test plots, but in practice you can't always extrapolate. You have to look at each district in turn. Some just aren't suitable," the official said.
Jose Jesus Perez de Ziriza, a researcher at the Agricultural Technical Institute in northern region Navarra, said conservation agriculture required more awareness and long-term planning to become widespread in Spain.
"Farmers want to use the same machinery to plant all their dry crops (mostly wheat and barley) at once and leave them," Perez de Ziriza said. "But what we see is that in the end there is no conservation and you have more diseases and more problems with weeds."