Document Type

Thesis - Open Access

Award Date

1988

Degree Name

Doctor of Philosophy (PhD)

Department

Agronomy

First Advisor

Gary D. Lemme

Abstract

The management problems associated with utilizing a single cropping system across an undulating landscape that contains well and poorly drained soils were addressed. Results from this work will aid farmers in making their tillage and crop rotation decisions. Four tillage treatments (moldboard plow, chisel plow, ridge-till and no-till) and three cropping sequences (continuous corn, corn after soybean, and soybean after corn) were arranged in a split plot design on a well drained Beadle and poorly drained Worthing soils. Worthing soil surface has a signlficant1y lower hydraulic conductivity and higher volumetric moisture, pH, available phosphorus and potassium than the Beadle soil. Crop emergence and grain yield were significant1y reduced in the Worthing soil compared to the Beadle soil across all tillage systems. Ridge-till and no-till treatments behaved differently from mdldboard and chisel plow treatments with respect to overall physical properties in the Beadle soil. Ridge-till and no-till plots had significantly higher volumetric moisture, lower soil temperature and higher bulk density than the moldboard plow and chisel plow plots. No significant difference in water use (evapotranspiration) was observed between tillage treatments in either soil. Little difference in physical properties of the Worthing soil was observed due to tillage except for a higher bulk density in the ridge and no-till treatments than other tillage treatments. Few differences in chemical properties due to tillage systems were found in these soils. A significantly higher pH was observed in the moldboard plow and chisel plow Beadle plots than in the ridge-till and no-till plots. Ridging in the Worthing soil significantly increased nitrate levels at 0-0.60 m compared to chiseling and no-till treatments. Little difference in crop development and grain yield was observed in either soil due to tillage in 1986. Moldboard plowed Beadle plots under continuous corn produced significantly higher leaf area most of the growing season and grain yield than other tillage treatments in 1987. Moldboard plow behaved differently from other treatments with respect to agronomic parameters in the Worthing soil in 1987 due to delayed plowing and the resulting cloddy surface. Ridge-till or no-till systems with corn-soybean rotations were found to be the best cropping systems practices in fields comprised of different proportions of well and poorly drained soils.

Library of Congress Subject Headings

Crop rotation

Tillage

Soil productivity

Format

application/pdf

Number of Pages

229

Publisher

South Dakota State University

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