Ammonia Volatilization from Soils1
- Harry A. Mills,
- Allen V. Barker and
- Donald N. Maynard2
If NH4+-N fertilizers are used, most agronomic crops grow best if the soil reaction is near neutrality. Previous studies have shown that if the soil pH becomes alkaline, NH3 volatilization losses of N occurs. The objective of this study was to determine whether or not a rapidly growing crop could reduce the volatilization losses of N, especially from soils above pH 7 to which large applications of NH4+-N fertilizers were made. This study was conducted in a greenhouse using a closed system in which all NH3 evolved from the soil was swept away by a stream of air and collected. The amount of NH3-N evolved from the soils was measured as a function of time, soil pH, amount of N application, and presence or absence of corn (Zea mays indentata Bailey) seedlings. Ammonia losses with or without plants in the system increased as the soil reaction and amount of NH4+-N application increased. A sharp upward inflection in NH3-N loss occurred at pH 7.2. Plants reduced NH3-N losses by atleast 60% in the alkaline soils and by lesser amounts in the acidic and neutral soils. Rapid absorption of NH4+-N by plant roots appeared to account for the conservation of N.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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