Factors Affecting Denitrification in a Sonoran Desert Soil1
- R. L. Westerman and
- T. C. Tucker2
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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