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Cattle Slurry Affects Nitrous Oxide and Dinitrogen Emissions from Fertilizer Nitrate
Author(s) -
Stevens R. James,
Laughlin Ronald J.
Publication year - 2001
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/sssaj2001.6541307x
Subject(s) - nitrous oxide , denitrification , flux (metallurgy) , fertilizer , nitrification , nitrogen , slurry , chemistry , nitrate , zoology , environmental science , agronomy , environmental chemistry , environmental engineering , organic chemistry , biology
Readily decomposable C in organic manures could enhance denitrification of NO 3 existing in soil. The worst scenario occurs when farmers apply manures and NO 3 ‐containing fertilizers at the same time to meet the nutrient requirements of the next crop. If the denitrification produced N 2 O rather than N 2 , the emission factor of 1.25% of fertilizer N used to calculate national inventories for N 2 O would be an underestimate for this farming practice. We used the 15 N gas–flux method to measure N 2 O and N 2 fluxes from grassland when cattle slurry (CS) containing 60 kg NH 4 –N ha −1 and KNO 3 (60 kg N ha −1 ) were applied at the same time. By labeling the KNO 3 and the NH 4 in CS, we quantified the processes producing N 2 O and checked for N 2 production by microbial processes other than denitrification. On average over field experiments replicated in March, May, August, and September 1997, CS increased the flux of N 2 O by 0.63% of the applied NO 3 –N in the 104 h after application, but had no significant effect on the flux of N 2 The maximum flux of N 2 O was always observed in the first measurement period (5–7 h) after CS application. All of the N 2 O was formed by reduction from NO 3 apart from in August when 10% was formed by nitrification in the CS treatment. There was no evidence for production of N 2 by other processes such as heterotrophic nitrifier denitrification or anaerobic NH 4 oxidation.