Tillage practices and soil degradation in the wheat cropping systems of the warmer areas of Africa and Asia
1990
Lal, R. (The Ohio State University, Columbus, Ohio (USA). Department of Agronomy)
Soil degradation, due to physio chemical and biological processes set in motion by anthropogenic factors, is a widespread problem in the warm wheat growing regions of Africa and Asia. Decline in structural conditions and reduction in quality and quantity of soil organic matter lead to crusting, compaction, low infiltration rate, high surface runoff, and accelerated soil erosion. The latter is a serious problem in ecologically sensitive regions in South Asia and East Africa. Some irrigated wheat producing arid and semi arid regions in South and West Asia are highly prone to salinization and alkalization. Soils intensively cultivated to the wheat rice rotation in South Asia are particularly susceptible to salt imbalances in the root zone. The problem is further compounded by drought stress, high evaporative demand, and lack of plant available water reserves in the root zone. Competition by weeds and other pests can also be a severe yield constraint.A principal goal of soil surface management is to alleviate these constraints, improve wheat production, and enhance soil quality. When available, using crop residue mulches and other organic wastes improve water storage in the root zone. Fallowing is another widely recommended practice for water conservation. The problem of soil compaction can be minimized through management of vehicular traffic. Guided traffic that reduces the number of passes of heavy machinery and zonal tillage such as ridge or chisel tillage are relevant practices toward a judicious management of soil compaction. There is no universal system for sustainable management of soil and water resources
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