Changes in Content of Total Nitrogen and Organic Matter in Three Nebraska Soils After Seven Years of Cropping Treatments
1966
Mazurak, Andrew P. | Conard, Elverne C.
Grasses compared with one another differed in their effect on the change in total N content of Brunizem soil at O- to 6-inch and 6- to 12-inch depths. However, the mean N content of soil cropped to grasses was not different from the mean for small grains. Plots that received ammonium nitrate fertilizer were significantly higher in total N content of soil in the O- to 6-inch depth than were the nonfertilized plots. Grasses growing on Chernozem soil reduced the total N content in die O- to 6-inch depth of the soil. The application of N fertilizer minimized the losses or increased the total N content of soil. Application of N fertilizer increased significantly the total N content of the O- to 6-inch depth of Chestnut soil. Cropping to grain on Chestnut and Chernozem soils necessitates the use of N fertilizer to maintain N content level in the soil. The effect of N fertilizer on the total N content of soil was evident in the O- to 6-inch depth but not in the 6- to 12-inch depth. Total oxidizable organic matter content showed the same results as the total N content in soil. Carbon/ nitrogen ratio of the soil was slightly increased during the 7 years of cropping to cool-season grasses. Warm-season grasses decreased C/N ratio in Brunizem soil.
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