|Unger, Paul -|
Submitted to: Advances in Soil Science
Publication Type: Book / Chapter
Publication Acceptance Date: October 10, 2011
Publication Date: May 15, 2012
Citation: Unger, P.W., Baumhardt, R.L., Arriaga, F.J. 2012. Mulch tillage for conserving soil water.In:Rattan Lal and B.A. Stewart (ed.)Soil Water and Agronomic Productivity. Boca Raton, London, New York: CRC Press, Taylor & Francis Group. p. 427-453. Technical Abstract: Mulching is the practice of maintaining organic or inorganic materials on or applying them to the soil surface. It is an ancient practice, but through the years clean tillage that incorporated crop residues and also controlled weeds became the norm. Frequent and deep tillage often was promoted to conserve soil water. Clean and deep tillage conserved water, but caused soil aggregate breakdown, surface sealing, and excessive runoff during major rainstorms, which led to serious soil erosion by water. Clean tillage also contributed to the disastrous soil erosion by wind during the major drought in the United States Great Plains in the 1930's. Stubble-mulch tillage, which undercuts the soil surface, leaves crop residues of the surface, and roughens the soil surface, was developed to help control the erosion. It was soon found that retaining residues on the surface also provided for conserving soil water, with water conservation generally increasing with increases in the amount of residues retained on soil surface. Research involving various types of mulch tillage has been conducted at numerous locations throughout the world. Mulch tillage is possible with a variety of implements, but careful implement selection is essential to retain the optimum amount of residues on the surface to achieve soil water conservation; also soil conservation and effective weed control. Weed control under mulch tillage conditions (also with other tillage methods) received a major boost with the development of herbicides, beginning in the 1940's. Improved herbicides developed since then now make it possible to achieve complete weed control with herbicides and produce crops by the ultimate mulch tillage method, namely, no-tillage, under many conditions. Use of no-tillage retains most crop residues on the surface, thereby providing the greatest opportunity for conserving soil water and subsequently achieving favorable crop production.