The Influence of Cation Exchange Capacity and Depth of Incorporation on Ammonia Volatilization from Ammonium Compounds Applied to Calcareous Soils
1976
Fenn, L. B. | Kissel, D. E.
The objective of this study was to determine the influence of soil cation exchange capacity (CEC) and depth of incorporation on NH₃-N volatilization from NH₄⁺-N compounds applied to calcareous soil. This study was conducted in the laboratory on soils with a wide range of CEC. An increasing CEC resulted in decreasing NH₃ losses. Ammonium sulfate produced higher soil pH values and NH₃ losses than did NH₄NO₃. The pH of the soil decreased with increasing NH₄NO₃ application rates. With NH₄NO₃, percent NH₃-N losses decreased with increasing application rate; however, with (NH₄)₂SO₄, percent NH₃-N losses increased as the application rates increased. Incorporation of the NH₄⁺-compounds into the soil reduced NH₃ losses. Increasing depths of NH₄⁺-incorporation resulted in reduced NH₃ loss. Losses decreased as the CEC of soil increased. The effectiveness of soil depth in reducing NH₃ loss was associated with soil water content. Decreasing the soil water increased the effectiveness of soil incorporation for reducing NH₃ losses. Two regression equations were developed to describe NH₃ losses with respect to CEC, soil pH, time, NH₄⁺-N application rate and temperature. Correlation coefficients were 0.86 and 0.81 for (NH₄)₂SO₄ and NH₄NO₃ systems, respectively.
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