Factors Affecting Denitrification in a Sonoran Desert Soil
1978
Westerman, R. L. | Tucker, Thomas Curtis
Incubation studies were conducted to determine the effect of temperature, moisture content, organic C, soil depth, and time on transformations of added ¹⁵NO₃-N to a Sonoran Desert soil in open and closed systems. In open system studies, increasing temperature from 20° to 37°C, adding organic C, and increasing moisture content from field capacity to saturation increased denitrification losses 16, 22, and 2%, respectively. There were no apparent differences in immobilization of ¹⁵NO₃-N due to temperature, time, moisture content, or soil depth without organic C amendments. However, immobilization of ¹⁵NO₃-N soils with organic C amendments was increased markedly with increased temperature and time, but initial moisture content had little effect. At C/N ratios of 150:1 only traces of ¹⁵N appeared in NH₄-N, however, at C/N ratios of 15:1 to 45:1 ammonification and immobilization occurred simultaneously. Closed system investigations with organic C and ¹⁵NO₃-N amendments showed 79% loss in 5 days with the remaining 21% accumulating as organic-¹⁵N. Denitrification losses in open systems with soil moisture contents representative of saturated conditions were 70% of the loss observed under closed systems at the same moisture content.
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