Challenge of Sustainable Agriculture

To increase food production, three avenues are available:

1. Extensification of agriculture;

2. Intensification of agriculture; and

3. Reduction of crop losses. Advances in the direction of extension of arable land, however, appear to have reached the limits of our present scientific and technological capabilities. In addition, there is growing competition for land for non-agricultural uses such as housing, industry and recreation. In poor countries with large agrarian sectors, population pressure on the land is degrading the basic biological, soil and water resources upon which agriculture depends. Further expansion of agricultural areas can only be made at unacceptable environmental costs and loss of sustainability.

A second means of increasing food production would be to intensify cultivation and increase yields from lands which are presently agriculturally viable. This intensification is achieved through greater energy inputs, irrigation, chemical fertilizers and pesticides, combined with genetic materials that are responsive to high inputs. These were the objectives of agricultural policies and research programs in the last few decades, when the development and spread of high yielding varieties of major crops resulted in large increases in production (the green revolution). These gains may have had costs which were not foreseeable at the time. One major cost was environmental, including pollution, agricultural wastes and reduced sustainability of agricultural ecosystems.

Monoculture of high yielding varieties has made crops more vulnerable, in the long run, to the resilience of endemic pests and diseases, which adapted to the expanded and homogenized host environment. This leads to an increase in pest infestations and increased use of pesticides in an escalating treadmill of action and reaction, and higher production costs and damage to the environment.1

The biggest danger of monoculture lies in the reduction of genetic diversity. Crop failures due to genetic uniformity are well documented. To cite a few of the major examples of overdependence on a narrow genetic base, leading to devastating crop diseases: The potato blight in Ireland in 1846 wiped out the entire crop upon which Ireland's poor depended, contributing to the famine which followed; crop disease led to the destruction of three million tons of rice in Indonesia in 1974; and one billion dollars' worth of the US maize crop was lost in 1970 due to the corn leaf blight.2 More recently, taro leaf blight has eliminated entire populations of this traditional staple food of the South Pacific nations.

The third means of increasing food production tackles this problem of reducing crop losses. It proposes to secure and increase agricultural productivity through means which break or circumvent the "pesticide treadmill" pattern and which restore a sustainable balance of organisms in the ecosystem. It has been suggested that by adopting integrated pest management approaches, including post-harvest management, global food availability could be doubled. Techniques include the judicious and reduced use of pesticides, multicropping to avoid monoculture and the introduction of pest-resistant cultivars.1

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