|UNGER P W|
|JONES O R|
|SCHOMBERG H H|
Submitted to: Trends in Agricultural Science
Publication Type: Literature Review
Publication Acceptance Date: 9/27/1994
Publication Date: N/A
Interpretive Summary: Residue management has been an integral part of crop production research in the SGP since the 1930s' drought, but the research emphasis has changed through the years to meet changing priorities. The early research, concerned with development of practices to control mainly wind erosion, led to development of SMT. Research soon showed that use of SMT, which retained more crop residues on the soil surface than clean tillage, also increased soil water conservation. Protection against erosion and amount of water conserved increased with increases in amounts of surface residues. As a result, subsequent research focused on development of practices that permitted effective and economical crop production under conditions that retained more surface residues. A major boost was the introduction of herbicides to control weeds. As a result, some or all tillage for weed control could be eliminated, which allowed more residues to be retained on the soil for soil and water conservation purposes. Presently, the emphasi is on obtaining a better understanding of processes controlling residue decomposition and on developing improved practices for presently-used and potential alternative crops.
Technical Abstract: Crop residue management has received much attention in the semiarid southern U.S. Great Plains since severe wind erosion damaged millions of hectares of land in the region during the severe drought of the 1930s. Research at several Great Plains locations during the 1940s and 1950s resulted in development of stubble mulch tillage (SMT), which is widely used throughout the Great Plains. Besides aiding wind erosion control, SM also aids water erosion control and water conservation. However, even greater soil and water conservation benefits occur when conservation tillage (CST) practices are used that retain most crop residues on the surface, as with no-tillage. Such systems have been investigated for most crops of the region under dryland (non-irrigated), limited irrigation, and full irrigation conditions, and favorable results usually were obtained when adequate residues were available. With limited residue production, as sin some cases of dryland cropping, the potential for soil and water conservation is reduced, but effective systems are available. Current residue management research in the region is aimed at understanding the processes controlling residue decomposition and in developing improved CST practices for presently-used and potential alternative crops and cropping systems.