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Impacts of low‐disturbance dairy manure incorporation on ammonia and greenhouse gas fluxes in a corn silage–winter rye cover crop system
Author(s) -
Sherman Jessica F.,
Young Eric O.,
Jokela William E.,
Cavadini Jason
Publication year - 2021
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.1002/jeq2.20228
Subject(s) - manure , agronomy , greenhouse gas , secale , ammonia volatilization from urea , ammonia , fertilizer , nitrous oxide , environmental science , carbon dioxide , chemistry , silage , nitrogen , urea , cover crop , zoology , biology , ecology , organic chemistry
Manure and fertilizer applications contribute to greenhouse gas (GHG) and ammonia (NH 3 ) emissions. Losses of NH 3 and nitrous oxide (N 2 O) are an economic loss of nitrogen (N) to farms, and methane (CH 4 ), N 2 O, and carbon dioxide (CO 2 ) are important GHGs. Few studies have examined the effects of low‐disturbance manure incorporation (LDMI) on both NH 3 and GHG fluxes. Here, NH 3 , N 2 O, CH 4 , and CO 2 fluxes in corn ( Zea mays L.)–winter rye ( Secale cereale L.) field plots were measured under fall LDMI (aerator/band, coulter injection, strip‐till, sweep inject, surface/broadcast application, broadcast‐disk) and spring‐applied urea (134 kg N ha –1 ) treatments from 2013 to 2015 in central Wisconsin. Whereas broadcast lost 35.5% of applied ammonium‐N (NH 4 –N) as NH 3 –N, strip‐till inject and coulter inject lost 0.11 and 4.5% of applied NH 4 –N as NH 3 , respectively. Mean N 2 O loss ranged from 2.7 to 3.6% of applied total N for LDMI, compared with 4.2% for urea and 2.6% for broadcast. Overall, greater CO 2 fluxes for manure treatments contributed to larger cumulative GHG fluxes compared with fertilizer N. There were few significant treatment effects for CH 4 ( P > .10); however, fluxes were significantly correlated with changes in soil moisture and temperature. Results indicate that LDMI treatments significantly decreased NH 3 loss but led to modest increases in N 2 O and CO 2 fluxes compared with broadcast and broadcast‐disk manure incorporation. Tradeoffs between N conservation versus increased GHG fluxes for LDMI and other methods should be incorporated into nutrient management tools as part of assessing agri‐environmental farm impacts.