Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Biosystems Engineering Technology

Major Professor

Fred D. Tompkins

Committee Members

Luther R. Wilhelm, Donald D. Tyler


An evaluation of the capabilities of a microprocessor-based, tractor-mounted soil cone penetrometer for sustained acquisition of reliable, repeatable data was initiated. Based on in-field observations, the penetrometer electronic data handling package and hydraulic system were modified to allow improved machine performance.

The penetrometer was then used to collect soil data in soybean plots subjected to continuous annual applications of six different tillage practices. After data acquisition, analyses of variance were performed to determine depth of tillage influence and to indicate differences in soil strength which could be attributed to particular tillage practices. Effects of trafficking on soil strength properties were also determined using cone index. Results indicated that no-tillage plots continually cropped with soybeans followed by a wheat cover crop tended to have higher cone indices to a depth of 10 inches than any other tillage treatment. Highest cone index values were observed between 4 and 8 inches in depth for the various tillage treatments considered collectively. Wheel-track penetrations tended to have higher cone index values than either row-middle or under-row penetrations to a depth of 10 inches.

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