Soil management in the developing countries

The present world population of 6 billion will reach 8 billion by 2020 and 9.4 billion by 2050. By then, the population will have increased by another 575 million in India, 300 million in China, 200 million in Nigeria, 200 million in Pakistan, and 140 million in Ethiopia. Of the total world population, 8.2 billion will live in developing countries, of which 3 billion will reside in arid and semiarid environments. Thus, soil management challenges for developing countries include achieving food security with minimal risks to environment given per capita land area decreasing to <0.1 ha and per capita irrigated land area to <0.04 ha, severe scarcity of renewable fresh water resources, high risks of soil degradation by a wide range of degradative processes, resource-poor farmers, and weak institutional support. Productivity loss attributable to erosion-caused soil degradation is estimated at 18 million Mg of food staples per year at the 1990 level of yields for subSaharan Africa and 272 million Mg for the world at the 1996 level of production. The productivity loss at a landscape level may range from 0 (or even positive effect) to total crop failure. In addition to enhancing productivity per unit area and per unit time, soil management technologies must also address pressing environmental issues, especially with regard to the greenhouse effect and air quality, water quality, and land application of industrial and urban wastes. Enhancing food production would necessitate adoption of land saving technologies through agricultural intensification on prime agricultural land, conversion of marginal lands to other appropriate land uses, and restoration of degraded lands and ecosystems. Soil-specific technologies for agricultural intensification will have to be developed, fine-tuned, and adopted. These technologies will address the issue of: (i) enhancing soil structure, (ii) increasing nutrient use efficiency through integrated nutrient management and strengthening nutrient recycling mechanisms, (iii) conserving soil and water through residue management and adoption of conservation tillage, (iv) improving water use efficiency through development and adoption of efficient methods of water harvesting, recycling and irrigation, and (v) increasing cropping intensity. Improvements in rainfed agriculture through water conservation and enhancing water and nutrient use efficiencies will be a major challenge in subSaharan Africa, India, Central Asian countries, northeastern Brazil, and other semiarid regions of the developing world. Preventing and restoring degraded soils, enhancing soil C sequestration to mitigate the greenhouse effect, and decreasing risks of eutrophication of surface water and contamination of ground water will be priority issues. Soil scientists will need to work closely with those in the basic sciences to address the environmental concerns of agricultural intensification. There is a strong need for high quality, credible, innovative, original, and demand-driven research in soil science in developing countries. Research managers can facilitate achievements of goals of high quality science by creating a conducive and trustworthy work atmosphere and by rewarding productivity and merit.