Effect of Cultivation on the Nitrogen and Organic Carbon Contents of a Kansas Argiustoll (Chernozem)1
- J. A. Hobbs and
- C. A. Thompson2
As a continuation of a Kansas dryland-soil study, started in 1916, samples from 44 plots and 2 uncultivated areas at the Ft. Hays Experiment Station were analyzed to determine the effects of a single cropping system (fallowwheat-sorghum) from 1956(58) to 1966 on soil organic-matter content.
Surface soils containing more than 0.100% nitrogen in l958 generally lost nitrogen between 1958 and 1966; those containing less than 0.100% generally gained nitrogen. A regression equation developed from the relationship between 1958 nitrogen content and 1958-to-1966 loss (or gain) predicted an equilibrium-nitrogen content of 0.103%.
Nitrogen losses from surface soils followed a curvilinear tiend, as in earlier phases of this study. Relation between soil-nitrogen content and duration of cultivation, developed from a knowledge of nitrogen contents of unbroken sod and of cultivated plots from 1915 through 1966 predicted that, with the fallow-wheat-sorghum cropping system and no additional organic matter or commercial fertilizer, the soil-nitrogen content should stabilize eventually at 0.103%.
Subsoils (18 to 51 cm) lost nitrogen between 1958 and 1966, which contrasted with results from earlier samplings.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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