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Effects of Feeding Encapsulated Nitrate to Beef Cattle on Ammonia and Greenhouse Gas Emissions from Their Manure in a Short‐Term Manure Storage System
Author(s) -
Lee Chanhee,
Araujo Rafael C.,
Koenig Karen M.,
Hile Michael L.,
FabianWheeler Eileen E.,
Beauchemin Karen A.
Publication year - 2016
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/jeq2016.02.0056
Subject(s) - manure , zoology , ammonia , chemistry , manure management , nitrate , nitrous oxide , urea , beef cattle , dry matter , carbon dioxide , greenhouse gas , latin square , nitrogen , environmental chemistry , agronomy , food science , ecology , biology , fermentation , rumen , organic chemistry
A study was conducted to investigate effects of feeding encapsulated nitrate (EN) to beef cattle on ammonia (NH 3 ) and greenhouse gas emissions from their manure. Eight beef heifers were randomly assigned to diets containing 0 (control), 1, 2, or 3% EN (55% forage dry matter; EN replaced encapsulated urea in the control diet and therefore all diets were iso‐nitrogenous) in a replicated 4 × 4 Latin square design. Urine and feces collected from individual animals were reconstituted into manure and incubated over 156 h using a steady‐state flux chamber system to monitor NH 3 , methane (CH 4 ), carbon dioxide (CO 2 ), and nitrous oxide (N 2 O) emissions. Urinary, fecal, and manure nitrate (NO 3 − )–N concentration linearly increased ( P < 0.001) with feeding EN, and urinary urea concentration tended to be lower ( P = 0.078) for EN versus Control. The hourly emissions of NH 3 , CO 2 , and N 2 O (mg head −1 h −1 ) were not affected, although NH 3 emission rates tended to be lower ( P = 0.070) for EN compared with Control at 0 to 12 h. Cumulative NH 3 , CO 2 , and N 2 O emissions over 156 h were not affected, but CH 4 emissions were less (4.5 vs. 7.4 g head −1 ; P = 0.027) for EN compared with Control. In conclusion, although NH 3 emissions were initially lower for EN manures, total NH 3 emitted over 156 h was not affected. Dietary EN lowered CH 4 emissions from manure, and, despite greater NO 3 − concentrations in EN manure, N 2 O emissions were not affected in this short‐term incubation. Core Ideas Feeding encapsulated nitrate to beef heifers increased nitrate excretion by cattle. Methane from manure decreased up to 45% by feeding encapsulated nitrate. Ammonia, carbon dioxide, and nitrous oxide emissions from manure were not altered.