EFFECT OF CROP ROTATION AND TILLAGE SYSTEMS ON SOME SOIL PROPERTIES, ROOT DISTRIBUTION AND CROP PRODUCTION
Abstract
Tillage methods in the Corn Belt have changed rapidly in recent years. Tillage methods that eliminate moldboard plowing have become popular in localized areas. Also crop production has changed. Crop rotations that included grass-legume sod have changed to continuous corn and, more recently, the corn-soybean rotation has become a common agricultural practice in the region. A study of crop rotation and tillage systems has been conducted at the Purdue Agronomy Farm, on a Chalmers silty clay loam soil, since 1975. The objective of this research was to collect data on those plots to study how the tillage systems and crop rotations are affecting some soil physical properties of the soil such as bulk density, soil moisture content and soil temperature, residue cover, fertilizer incorporation, plant nutrition and root distribution, and how such changes affect crop growth and yield. Bulk densities were lowest in the chiseled plots and highest in the no-tilled plots. Soil temperatures were highest in the conventional and ridge system and lowest in the no-till. Soil temperatures were higher when the previous crop was soybeans rather than corn. Conventional tillage had lower soil moisture content than the other tillage systems especially in plots with corn residue. Lowest pH values were measured at 7.5-15 cm depth as a result of nitrogen incorporation at that depth. Moldboard plowing had phosphorus and potassium well distributed in the plowed layer. Chisel, ridge and no-till had these elements concentrated in the upper few cms. Some chemical elements in corn and soybean leaves were affected by the treatments. Corn rooting density was greater on the upper 7.5 cm soil depth and lower in the 7.5-15 cm soil depth in no-till than in chisel, ridge or the conventional systems. Soybean root density was higher in the upper layer and decreased with depth in all tillage systems. Even though the treatments affected several soil conditions and plant characteristics, soil temperature as a result of residue cover was the variable that most affect the differences in corn yield among the treatments. No significant correlation was found between soybean yield and any variable studied.
Degree
Ph.D.
Subject Area
Agronomy
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