Many of these changes are a direct result of manipulating bio-chemical cycles and energy flows, and relate especially to the use of chemical fertilizers and crop protection chemicals. While landscape change often rapid and observable, many of the changes that have occurred, and are continuing to occur, because of the application of agricultural chemicals, are less easy to pinpoint. Significant environmental impacts have ensued inadvertent consequences of such high technology agriculture. Soil erosion, Stalinization and desertification are some of the problems which are becoming increasingly alarming in the intensively cultivated cereal growing areas and in the semi-arid regions of the world. Agricultural methods in the last two decades, aimed at more intensive food production, have also caused the destruction of natural habitats at a hitherto unprecedented rate, a process that has generated considerable acrimony between agriculturalists and conservationists. Moreover, the use of crop protection chemicals has had widespread ecological repercussions.
It is not only the developed countries in which the environmental changes occurred, agriculture in the developing countries is also becoming more technologically, rather than traditionally based. In the past 30 years, global agriculture has made remarkable progress in expanding world food supplies. Although world population doubled over this period, food production rose even faster, so that the world’s croplands and pasturelands support an additional 1.5 billion people-today. Gains have been particularly significant in the developing world. Per capita food supplies in some of the developing countries (India, Pakistan, Brazil, Mexico, etc.
) rose from less than 2,000 calories per day in 1962 to more than 2,500 calories in 1995, driven by the combination of better seeds, expanded irrigation and high fertilizer and pesticides use what has become known as Green Revolution as well as by the rapid growth in food imports from the rest of the world (UNO, op. cit.). “Yield plateau” or “yield stagnation” has been detected in the case of wheat, rice and millets in the developing countries. Unfortunately, about 800 million of the world’s people 200 million of them children suffer from chronic under nutrition. The intensification of agriculture in the developing countries is causing environmental degradation.
The use and misuse of chemical fertilizers and new rotation of crops are changing the soil chemistry. Moreover, poor agricultural practices are degrading the soil. Soil-making processes are notoriously slow, requiring from 200 to 1,000 years forming 2.
5 cms of topsoil under normal agricultural conditions. More soil-friendly practices, therefore, need to be adopted. These methods include, contour farming, terracing, vegetative barriers, and improved land use practices at the farm level.