Author
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Aase, J |
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Submitted to: Yearbook of Science and Technology
Publication Type: Book / Chapter Publication Acceptance Date: 6/23/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Tillage is mechanical manipulation of soil. Common tillage practices include: Conventional tillage: Consists of primary and secondary tillage. Ridge tillage: Seedbeds are prepared on ridges produced with tillage implements. Stubble mulch tillage: Plant residues are minimally disturbed during tillage to leave a protective cover on soil surface. No-tillage: Soil is left undisturbed except for opening it with seed drill to place seed at intended depth. Various tillage practices have profoundly different influences on soil properties. Organic matter influences physical and chemical properties far beyond its presence. Organic matter can be maintained in semiarid agriculture by application of available manures or by practices that allow more crop residue returned to the soil as compared with fallow-crop production. Soil bulk density is dry weight of a unit volume of soil. In some studies bulk densities increased under no-tillage as compared to conventional tillage, in others it decreased. When tillage practices are changed, it takes several years for lasting soil changes to take place. Penetration resistance generally followed same trends as bulk density on the northern semiarid Great Plains. Results from southern Plains were mixed. Crop yields across the country are generally favorable for conservation tillage practices. Fallow practices may have their place, particularly during drought years. However, with modern, improved farming techniques, including appropriate use of herbicides, conserving soil water, and protecting soil from erosion, the general conclusion is that conservation-tillage farming is viable and that successful farming on the semiarid Great Plains need not include summer fallow. |
