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Thesis (M.S.)--University of Nebraska--Lincoln, 1951. Department of Agronomy.


Copyright 1951, the author. Used by permission.


The purpose of this paper is to present data comparing the effects of continuous plowing, continuous subsurface tillage, and surface application of straw on the nitrification rate and zone of maximum nitrification in the soil. Crop yields and field nitrate accumulation data collected at intervals during the years 1944 to 1950 inclusive at Lincoln, Nebraska, along with current nitrification rate studies, show no increase in the available nitrogen of a Sharpsburg silty clay loam soil in continuous corn as a result of the annual application of wheat straw surface mulches. As shown by the nitrification rate studies, there was no consistent difference in the soil zone of maximum nitrification with plowing versus stubble mulching.

Advisor: T.M. McCalla