Sustainable farming systems for dryland agriculture

Abstract

Arid and semiarid regions comprise almost 40% of the world’s land area and are inhabited by some 700 million people. Approximately 60% of these drylands are in developing countries. Low rainfall areas constitute from 75–100% of the land area in more than 20 countries in the Near East, Africa, and Asia. Farmers in these regions produce more than 50% of the groundnuts, 80% of the pearl millet, 90% of the chickpeas, and 95% of the pigeon peas. These dryland areas will continue to produce most of the world’s food grains for expanding populations in the years ahead. However, yields are extremely low compared with those of the humid and subhumid regions. In some countries of sub-Saharan Africa and the Near East food grain production per capita has declined significantly during the past decade. Although part of this decline can be attributed to high rates of population growth, periodic drought, and unfavorable agricultural production and marketing policies of the national governments, much of it results from the steady and continuing degradation of agricultural lands from soil erosion and nutrient depletion and the subsequent loss of soil productivity (FAO, 1986; Dregne, 1989).