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Temperature and Manure Placement in a Snowpack Affect Nutrient Release from Dairy Manure during Snowmelt
- Peter A. Vadas, Melanie N. Stock, Gary W. Feyereisen, Francisco J. Arriaga, Laura W. Good, K. G. Karthikeyan
- Journal of environmental quality 2018 v.47 no.4 pp. 848-855
- ammonia, risk, ammonium, application rate, dairy manure, liquid manure, melting, nitrogen, nutrient management, phosphorus, runoff, snow, snowmelt, snowpack, temperature, volatilization, water quality, winter
- Agricultural nutrient management is an issue due to N and P losses from fields and water quality degradation. Better information is needed on the risk of nutrient loss in runoff from dairy manure applied in winter. We investigated the effect of temperature on nutrient release from liquid and semisolid manure to water, and of manure quantity and placement within a snowpack on nutrient release to melting snow. Temperature did not affect manure P and NH₄–N release during water extraction. Manure P release, but not NH₄–N release, was significantly influenced by the water/manure solids extraction ratio. During snowmelt, manure P release was not significantly affected by manure placement in the snowpack, and the rate of P release decreased as application rate increased. Water extraction data can reliably estimate P release from manure during snowmelt; however, snowmelt water interaction with manure of greater solids content and subsequent P release appears incomplete compared with liquid manures. Manure NH₄–N released during snowmelt was statistically the same regardless of application rate. For the semisolid manure, NH₄–N released during snowmelt increased with the depth of snow covering it, most likely due to reduced NH₃ volatilization. For the liquid manure, there was no effect of manure placement within the snowpack on NH₄–N released during snowmelt. Water extraction data can also reliably estimate manure NH₄–N release during snowmelt as long as NH₃ volatilization is accounted for with liquid manures for all placements in a snowpack and semisolid manures applied on top of snow. CORE IDEAS: Nutrient loss in runoff from winter‐applied manure can be significant. Cold temperatures do not decrease nutrient release from manure to water. Nutrient release from manure during snowmelt is not a function of placement in a snowpack. Laboratory extraction data can be used to estimate nutrient release from manure during snowmelt. Solid manure may release less P during snowmelt than liquid manures.