135-4 Measuring the Effects of Water Table Management On Soil Greenhouse Gas Emissions From Corn and Soybean Fields In Eastern Canada.



Monday, October 17, 2011: 9:15 AM
Henry Gonzalez Convention Center, Room 218, Concourse Level

Vinay Nangia1, Mark Sunohara2, Ed Topp3, Edward G. Gregorich2, Natalie Gottschall2, Craig F. Drury4 and David R. Lapen2, (1)International Center for Agricultural Research in the Dry Areas (Formerly with Agriculture and Agri-Food Canada), Aleppo, Syria
(2)Eastern Cereal and Oilseed Research Center, Agriculture and Agri-Food Canada, Ottawa, ON, Canada
(3)Southern Crop Protection and Food Research Center, Agriculture and Agri-Food Canada, London, ON, Canada
(4)Agriculture and Agri-Food Canada, Harrow, ON, Canada
Controlled tile drainage (CTD) is a management practice that regulates the amount of tile drainage water that can leave a field thus allowing for crops to more readily access water and nutrients during critical crop growth stages. As a result soils are generally wetter under CTD which may influence GHG emissions. The objective of this study was to compare field emissions of soil CH4, N2O, and CO2 for fields under conventional (UTD) and controlled tile drainage (CTD) for corn/soybean cropping system in eastern Ontario, Canada. From 2005-09, soil GHG measurements were made from two field pairs with fields within each pair being of comparable size, soil types, and agronomic-cropping practices but differing only in how tile drainage was managed. The field conditions were wetter than the normal during 2006 and 2008 and drier than the normal during 2007 and 2009. There was no statistical difference (p>0.05) in log-transformed soil CH4 emissions between CTD and UTD for all years and all field pairs examined. The median CH4 emissions for the yearly monitoring periods ranged between 0.000 and 0.001 kg ha-1 day-1. Median yearly study season soil CO2 emissions ranged between 20 (CTD, corn, 2007) and 39 (CTD, soybeans, 2006) kg ha-1 day-1. Yearly log-transformed soil CO2 emissions differed statistically (p≤0.05) among the tile management practices during 2006 and 2007 (CTD>UTD emissions). The most important independent criteria delineating CO2 emission was soil temperature (positively) and N fertilizer rates (negatively). The yearly study season median soil N2O emissions ranged from 0.003 (UTD, corn, 2008) to 0.028 (CTD, corn, 2006) kg ha-1 day-1. For each year, the study season log-transformed soil N2O emissions did not differ statistically among CTD and UTD fields. N2O was most strongly linked (positively) to both soil NO3- concentrations and N fertilizer application rate and not the physical factors (e.g., soil-water content, water table depth) deemed to be most directly influenced by CTD practices.
See more from this Division: S06 Soil & Water Management & Conservation
See more from this Session: Agricultural Practices to Increase Nitrogen-Use Efficiency, Carbon Sequestration, and Greenhouse Gas Mitigation: I