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Fertilizer Source and Tillage Effects on Yield‐Scaled Nitrous Oxide Emissions in a Corn Cropping System
Author(s) -
Venterea Rodney T.,
Maharjan Bijesh,
Dolan Michael S.
Publication year - 2011
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/jeq2011.0039
Subject(s) - tillage , agronomy , nitrous oxide , fertilizer , conventional tillage , urea , environmental science , sowing , nitrogen , greenhouse gas , crop yield , yield (engineering) , chemistry , zoology , biology , ecology , materials science , organic chemistry , metallurgy
Management practices such as fertilizer or tillage regime may affect nitrous oxide (N 2 O) emissions and crop yields, each of which is commonly expressed with respect to area (e.g., kg N ha −1 or Mg grain ha −1 ). Expressing N 2 O emissions per unit of yield can account for both of these management impacts and might provide a useful metric for greenhouse gas inventories by relating N 2 O emissions to grain production rates. The objective of this study was to examine the effects of long‐term (>17 yr) tillage treatments and N fertilizer source on area‐ and yield‐scaled N 2 O emissions, soil N intensity, and nitrogen use efficiency for rainfed corn ( Zea mays L.) in Minnesota over three growing seasons. Two different controlled‐release fertilizers (CRFs) and conventional urea (CU) were surface‐applied at 146 kg N ha −1 several weeks after planting to conventional tillage (CT) and no‐till (NT) treatments. Yield‐scaled emissions across all treatments represented 0.4 to 1.1% of the N harvested in the grain. Both CRFs reduced soil nitrate intensity, but not N 2 O emissions, compared with CU. One CRF, consisting of nitrification and urease inhibitors added to urea, decreased N 2 O emissions compared with a polymer‐coated urea (PCU). The PCU tended to have lower yields during the drier years of the study, which increased its yield‐scaled N 2 O emissions. The overall effectiveness of CRFs compared with CU in this study may have been reduced because they were applied several weeks after corn was planted. Across all N treatments, area‐scaled N 2 O emissions were not significantly affected by tillage. However, when expressed per unit yield of grain, grain N, or total aboveground N, N 2 O emissions with NT were 52, 66, and 69% greater, respectively, compared with CT. Thus, in this cropping system and climate regime, production of an equivalent amount of grain using NT would generate substantially more N 2 O compared with CT.