Long-term no-till and stover retention each decrease the global warming potential of irrigated continuous corn

Authors

Virginia L. Jin, USDA-ARSFollow
Marty R. Schmer, USDA-ARSFollow
Catherine E. Stewart, USDA-ARSFollow
Aaron J. Sindelar, USDA-ARSFollow
Gary E. Varvel, USDA-ARSFollow
Brian J. Wienhold, USDA-ARSFollow

Date of this Version

2017

Citation

Global Change Biology, 2017. doi: 10.1111/gcb.13637

Comments

U.S. government work.

Abstract

Over the last 50 years, the most increase in cultivated land area globally has been due to a doubling of irrigated land. Long-term agronomic management impacts on soil organic carbon (SOC) stocks, soil greenhouse gas (GHG) emissions, and global warming potential (GWP) in irrigated systems, however, remain relatively unknown. Here, residue and tillage management effects were quantified by measuring soil nitrous oxide (N2O) and methane (CH4) fluxes and SOC changes (ΔSOC) at a long-term, irrigated continuous corn (Zea mays L.) system in eastern Nebraska, USA. Management treatments began in 2002, and measured treatments included no or high stover removal (0 or 6.8 Mg DM ha^-1 yr^-1, respectively) under no-till (NT) or conventional disk tillage (CT) with full irrigation (n = 4). Soil N2O and CH4 fluxes were measured for five crop-years (2011 to 2015), and ΔSOC was determined on an equivalent-mass basis to ~30 cm soil depth. Both area- and yield-scaled soil N2O emissions were greater with stover retention compared to removal and for CT compared to NT, with no interaction between stover and tillage practices. Methane comprised