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Nitrous Oxide Flux from Solid Dairy Manure in Storage as Affected by Water Content and Redox Potential
Author(s) -
Brown H. A.,
WagnerRiddle C.,
Thurtell G. W.
Publication year - 2000
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 - 10.2134/jeq2000.00472425002900020034x
Subject(s) - manure , nitrous oxide , chemistry , straw , amendment , nitrogen , flux (metallurgy) , analytical chemistry (journal) , water content , zoology , environmental chemistry , agronomy , inorganic chemistry , geotechnical engineering , organic chemistry , political science , law , biology , engineering
The current global N 2 O budget estimates that animal production contributes one third of agricultural emissions. A study was conducted on solid dairy manure to determine the potential for N 2 O emission during storage. A laboratory flow‐through chamber and tunable diode laser analyzer were employed to continuously quantify the N 2 O flux in a temperature‐controlled environment. Water, NO 3 ‐N and NH 4 ‐N contents and redox potential ( E h , using a platinum and Ag‐AgCl reference electrode) also were monitored. In Experiment 1, manure samples were collected (4.3 kg wet weight) from three layers near the surface of the pile (0–15, 15–30, and 30–45 cm) and incubated at 22°C for 20 d. The mean daily N 2 O‐N fluxes were between 0 and 0.33 g N m −2 d −1 , and N 2 O was only generated in samples from the top two layers of the pile. In Experiment 2, samples from the 30‐ to 45‐cm depth were adjusted by amendment with chopped straw to 70, 75, and 80% water content (WC). These samples showed less variable fluxes and produced twice as much N 2 O‐N as the unamended samples. Levels of straw‐amendment had no significant effect on N 2 O emissions. Combined results from both experiments revealed that fluxes were highest at 55 to 70% WC and 150 to 250 mV E h . The N 2 O emission was limited by low NO 3 ‐N levels in samples with high WC and low E h . Increasing WC and decreasing E h with depth and increasing levels of NO 3 in the surface layer over time revealed that the exterior of solid manure piles is crucial to the flux of N 2 O.