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Greenhouse Gas Emissions from an Irrigated Crop Rotation Utilizing Dairy Manure
Author(s) -
Leytem A. B.,
Moore A. D.,
Dungan R. S.
Publication year - 2019
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2018.06.0216
Subject(s) - manure , greenhouse gas , fertilizer , environmental science , irrigation , agronomy , crop rotation , water content , growing season , moisture , manure management , zoology , crop , chemistry , geotechnical engineering , engineering , ecology , biology , organic chemistry
Core Ideas Manure addition enhanced N 2 O losses. 0.13 to 0.24% of total N added was lost as N 2 O. Overall, global warming potential was lower in manure treatments than in fertilizer treatments. Information on greenhouse gas (GHG) emissions from manure application in cropping systems of the irrigated mountain west region is needed. The objectives of this study were to (i) determine the effect of manure application rate and frequency (annual vs. biennial) on GHG losses compared to synthetic fertilizer, (ii) determine the effect of irrigation on GHG losses and (iii) determine the overall global warming potential (GWP) of using manure vs. synthetic fertilizer. Treatments included dry manure rates of 18 or 52 Mg ha −1 applied annually or 36 Mg ha −1 applied biennially as well as synthetic fertilizer and control treatments. Cumulative losses of N 2 O‐N over the rotation ranged from 1.4 to 8.4 kg ha −1 with the 52 Mg ha −1 manure application losing the greatest amount of N 2 O‐N. Emission factors for the growing season indicated that 0.13 to 0.24% of total N applied was lost as N 2 O‐N. Cumulative CO 2 –C losses were greatest in the manure treatments, with approximately 7% of carbon added lost as CO 2 –C. Maximum N 2 O‐N fluxes occurred at soil moisture contents of 0.3 to 0.4 m 3 m −3 and temperature near 25°C, while CO 2 –C emissions occurred over broader soil moisture and temperature conditions. The overall GWP associated with manure application indicated a net negative GWP for manure treatments while the synthetic fertilizer treatment was near neutral. Including manure in cropping system rotations can lead to enhanced GHG emission, however the benefits of enhanced SOC can outweigh these losses leading to lower GWP than use of synthetic fertilizer alone.