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Nitrogen Oxide and Methane Emissions under Varying Tillage and Fertilizer Management
Author(s) -
Venterea Rodney T.,
Burger Martin,
Spokas Kurt A.
Publication year - 2005
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/jeq2005.0018
Subject(s) - tillage , nitrous oxide , greenhouse gas , carbon dioxide , methane , environmental science , fertilizer , conventional tillage , agronomy , chemistry , nitrogen , zoology , ecology , organic chemistry , biology
Comprehensive assessment of the total greenhouse gas (GHG) budget of reduced tillage agricultural systems must consider emissions of nitrous oxide (N 2 O) and methane (CH 4 ), each of which have higher global warming potentials than carbon dioxide (CO 2 ). Tillage intensity may also impact nitric oxide (NO) emissions, which can have various environmental and agronomic impacts. In 2003 and 2004, we used chambers to measure N 2 O, CH 4 , and NO fluxes from plots that had been managed under differing tillage intensity since 1991. The effect of tillage on non‐CO 2 GHG emissions varied, in both magnitude and direction, depending on fertilizer practices. Emissions of N 2 O following broadcast urea (BU) application were higher under no till (NT) and conservation tillage (CsT) compared to conventional tillage (CT). In contrast, following anhydrous ammonia (AA) injection, N 2 O emissions were higher under CT and CsT compared to NT. Emissions following surface urea ammonium nitrate (UAN) application did not vary with tillage. Total growing season non‐CO 2 GHG emissions were equivalent to CO 2 emissions of 0.15 to 1.9 Mg CO 2 ha −1 yr −1 or 0.04 to 0.53 Mg soil‐C ha −1 yr −1 Emissions of N 2 O from AA‐amended plots were two to four times greater than UAN‐ and BU‐amended plots. Total NO + N 2 O losses in the UAN treatment were approximately 50% lower than AA and BU. This study demonstrates that N 2 O emissions can represent a substantial component of the total GHG budget of reduced tillage systems, and that interactions between fertilizer and tillage practices can be important in controlling non‐CO 2 GHG emissions.