|LEE, CHANHEE - Pennsylvania State University|
|HRISTOV, ALEX - Pennsylvania State University|
|KAYE, JASON - Pennsylvania State University|
|BEEGLE, DOUGLAS - Pennsylvania State University|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2013
Publication Date: 6/23/2014
Publication URL: http://handle.nal.usda.gov/10113/60619
Citation: Lee, C., Feyereisen, G.W., Hristov, A.N., Dell, C.J., Kaye, J.P., Beegle, D.B. 2014. Effects of dietary protein concentration on ammonia volatilization, nitrate leaching, and plant nitrogen uptake from dairy manure applied to lysimeters. Journal of Environmental Quality. 43(1):390-408.
Interpretive Summary: Management of nitrogen (N) in animal and crop agriculture continues to be an environmental concern. The objective of this experiment was to determine the uses and losses of N from dairy manure applied to soil to fertilize a subsequent crop. Manure was obtained from lactating dairy cows fed diets with two different crude protein levels, HighCP (16.7%) and LoCP (14.8%). Urine and feces were labeled with 15N and both labeled and unlabeled urine and feces samples were collected. The components were mixed and immediately applied to 61 by 61 by 61-cm blocks of soil in a greenhouse environment. The total N application rate was equivalent for all treatments: 277 kg tot-N/ha. Ammonia emissions were measured for a 100-h period after application. The manure was incorporated into the soil and a simulated rainfall event leached water through the soil profile. Leachate was sampled and tested for nitrate-N concentration. A spring barley crop was planted and raised through senescence. Plant and soil samples were collected throughout the experiment. The fate of the 15N was tracked by isotopic analysis. There was no difference in whole-crop barley N yields between LowCP and HighCP manures, but barley kernel N yield tended to be greater for lysimeters treated with HighCP manures. With both LowCP and HighCP manures, a greater proportion of urinary vs. fecal N was recovered in leachate nitrate-N. Ammonia emission rates and the contribution of urinary N to nitrate-N were on average about 100% greater for HighCP vs. LowCP manures. Applied at equal N soil application rates, manure from cows fed 16.7% CP diet resulted in markedly greater ammonia emissions and urinary N losses in leachate than manure from cows fed a 14.8% CP diet. The research will benefit other researchers seeking to improve N use in animal-crop agricultural systems. The findings will inform those in the dairy industry as to the environmental outcomes of using high vs. low CP diets.
Technical Abstract: This lysimeter experiment was designed to investigate the effects of dietary crude protein (CP) concentration on nitrate-N (NO3-N) and ammonia (NH3) losses from dairy manure applied to soil and manure N use for plant growth. Lactating dairy cows were fed diets with 16.7 (HighCP) or 14.8% (LowCP) crude protein content. Feces and urine were labeled with 15N by ruminal pulse-doses of 15NH4Cl. Unlabeled and 15N-labeled feces and urine were used to produce manure for a study with 21 lysimeters in a greenhouse. Manure application rate was 277 kg N/ha. Ammonia emissions were measured at 3, 8, 23, 28, 54, and 100 h after manure application. Manure was incorporated into the soil and a leaching event was simulated. Spring barley was planted (387 plants/m2) 7 d after the leaching event and harvested at senescence. There was no difference in whole-crop barley N yields between LowCP and HighCP manures, but barley kernel N yield tended to be greater (P = 0.09) for lysimeters treated with HighCP manures. With both LowCP and HighCP manures, a greater proportion of urinary vs. fecal N was recovered in leachate NO3-N. Ammonia emission rates and the contribution of urinary N to NO3-N were on average about 100% greater for HighCP vs. LowCP manures. Applied at equal N soil application rates, manure from cows fed 16.7% CP diet resulted in markedly greater NH3 emissions and urinary N losses with leachate N NO3-N than manure from cows fed a 14.8% CP diet.