Conservation of Soil Nitrogen in a Wheat Summer Fallow Farming Practice
1966
Comparisons were made on the effect wheat straw had on the soil nitrogen and on the yield of wheat, in a wheat summer fallow system of cropping from 1931 to 1964. When the wheat straw was burned, either in the fall following the crop or in the spring before plowing, the soil nitrogen level showed a continuous downward trend over the 34-year cropping period. When the wheat straw was returned to the soil without added nitrogen in some form, no additional benefit was gained over burning the straw, either in retaining the soil nitrogen or increasing wheat yields. When some form of nitrogenous fertilizer, either as legume straw, strawy manure, or commercial fertilizer was added to the wheat straw before plowing, the results were improved nitrogen retention and increased wheat yields. The yields of wheat over the period studied showed a definite relationship to the total nitrogen level found in the surface foot of soil.
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