Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 9, 2000
Publication Date: N/A
Technical Abstract: This work evaluated soil CO2 concentrations and tillage-induced CO2 losses after one season of decomposition with no additional carbon input. The objective was to evaluate the long-term effects of moldboard plowing on CO2 loss from a Barnes loam (Udic Haploborolls, fine-loamy, mixed) in west central Minnesota, USA. Tillage-induced CO2 loss was periodically measured dusing a large portable chamber during summer of 1999. The soil CO2 concentration was measured at 5, 10, 20, 30, 50 and 70-cm depths in the no- till plots and 30, 50 and 70-cm depths in plowed plots. The initial flush of CO2 immediately after moldboard plowing was only 8.1 g CO2 m-2 h-1 while that from the not-tilled treatment was less than 0.3 g CO2 m-2 h-1. For the 132-day period following tillage, the cumulative CO2 flux from the plowed treatment was 2.0 times higher that from not tilled. Carbon dioxide concentrations were highest at the 30, 50, 70-cm depths. Maximum CO2 concentrations at all depths and tillage-induced CO2 losses were lower during the season one year after wheat harvest. These results suggest much labile carbon had been oxidized shortly after harvest.