Ammonia Volatilization from Liquid Swine Manure Applied to Cropland1
- J. D. Hoff,
- D. W. Nelson and
- A. L. Sutton2
Randomized complete block design field experiments were conducted to determine the effects of rates and methods of liquid swine manure application on volatile NH3-N losses from cropland. In addition, a greenhouse study was conducted to determine the effect of wind on the rate of NH3-N volatilization from soil and the accuracy of NH3-N loss measurements under field conditions. A partially closed system was utilized to directly collect volatilized NH3-N from microplots.
The NH3-N collection system did not accurately estimate volatile N losses when windy conditions existed as often encountered in the field. Using direct measurement of NH4+-N in waste before and after exposure to the atmosphere to correct for the low estimates of NH3-N loss under field conditions, an average of 48.1% of the volatilized N was collected under greenhouse conditions with relatively constant temperature and wind.
The rate of NH3-N loss from manure increased with increasing temperature and air movement. The proportions of the applied NH4+-N lost as NH3-N during a 3.5-day sampling period in the spring from swine manure (pH 6.4) applied to soil (pH 6.4) and corrected for the effect of wind were: 14.0%, 12.2%, and 11.2% for the 90, 135 and 180 metric ton/ha, respectively, of surface applied liquid swine manure; 2.5% for both the 90 and 180 metric ton rates, respectively, of injected liquid swine manure; 14.7% for surface applied urea fertilizer (168 kg N/ha); and 65.8% of the applied NH4+-N from swine manure surface applied (90 metric tons/ha) on a plastic liner. Fresh swine manure (pH 7.8) surface applied at the rate of 135 metric tons/ha on greenhouse loam soil (pH 7.0) lost 82.5% of the applied NH4+-N in an 8-day sampling period.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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