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Conservation for greater sustainability

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09.06.2006

Agriculture necessarily entails interactions between man and the environment, and while the advantages are clear, there are also drawbacks: reduced biodiversity, poorer soil quality, and a reduction in the amount of water available and its quality. One of the possible solutions, conservation agriculture, aims to preserve and improve the soil and the life associated with it. It combines three principles: a reduction in or the elimination of soil tillage, permanent soil cover, and the introduction of tailor-made, more diverse rotations. Conservation agriculture is now being practised on more than 95 million hectares worldwide*.

However, although conservation agriculture has now been adopted by the main producing countries, it is not easily applicable in every situation. The KASSA project, coordinated by CIRAD, has spent 18 months taking stock of the available information on this particular type of sustainable agriculture. It has involved partners from 28 research and development organizations in 18 countries in Europe, North Africa, Asia and Latin America.

Conservation agriculture is spreading fast, but not everywhere

The first observation: more and more farmers in a growing number of countries are adopting conservation agriculture. This growth has been particularly marked in the main producing and selling countries in South and North America** and in Australia. Whereas in 1990, the technology was in use on less than 10 million hectares in Latin America, it now concerns more than 40 million. In India, the area under wheat with no-till has grown exponentially: from 400 hectares in 1998 to almost 2.2 million in 2005.

Europe, however, is still lagging behind, despite the interest shown in research circles in no-till and reduced soil tillage between the early 1960s and the 1990s. In Spain, conservation agriculture has been practised since the 1980s, although the exact area concerned is not known. In central and eastern Europe, in both the Baltic countries and south of the Mediterranean, systems based on conservation agriculture are gradually beginning to appear***. And for good reason: conservation agriculture quickly enables farmers to make substantial savings in terms of energy, machinery and above all workload, in a situation of ever-growing competition.

Reduced production costs have triggered interst among farmers

What are the reasons for this disparity? Various constraints dissuade farmers from embarking upon conservation agriculture or mean that they only use part of the technology. In effect, certain soil types (those that are susceptible to compaction, humid, etc) or climates (very humid, cold or too arid) do not lend themselves to the technique. Permanent cover and rotation in particular are supposed to protect the soil against erosion and control weeds, pests and diseases, but they mean increased costs for farmers: crops grown in rotation do not always find market outlets; in some cases, cover fosters pest and disease development; and suitable plants and varieties are still in short supply. This accounts for the often intensive use of pesticides.

Moreover, in Europe, production levels are already very high, and introducing conservation agriculture does not produce very spectacular increases in yields (+/- 10%). The only real advantage is the reduction in production costs, and it is this that seems to be arousing the interest of European farmers at present.

It is still necessary to develop and improve the technology and adapt it to the different favourable situations. The impact of conservation agriculture on soil properties and functioning and on the micro- and macroorganisms that live in it is not yet fully understood. It is also important to look more closely at the consequences of the pollutants, heavy metals and pesticides used for soil and water quality and the food chain. Moreover, it is necessary to determine the social and economic repercussions, notably for employment, rural development (and particularly education and the situation of women in poor countries) and food prices. More generally, while the short-term benefits are sufficiently clear for conservation agriculture to have found a place in the landscapes of several continents, there are still many questions concerning its positive or negative impact in the long term.

Rabah Lahmar | Source: alphagalileo
Further information: www.cirad.fr/en/actualite/communique.php?id=472

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