Submitted to: USDA Symposium on Natural Resource Management to Offset Greenhouse Gas Emissions
Publication Type: Proceedings
Publication Acceptance Date: 11/21/2002
Publication Date: 11/21/2002
Citation: REICOSKY, D.C., LINDSTROM, M.J., SCHUMACHER, T.E., LOBB, D.E. TILLAGE-INDUCED VARIATION IN TERRESTRIAL CARBON STOCKS AND CO2 LOSS ACROSS AN ERODED LANDSCAPE. USDA SYMPOSIUM ON NATURAL RESOURCE MANAGEMENT TO OFFSET GREENHOUSE GAS EMISSIONS. 2002. P. 125.
Technical Abstract: Soil carbon (C) losses and soil translocation from tillage operations have been identified as causes of soil degradation and soil erosion. The objective of this work was to quantify the variability in terrestrial C stocks and tillage-induced CO2 loss by moldboard and chisel plowing across an eroded landscape. The study site was a 4-ha wheat field with rolling topography and three glacial till soils in the Barnes-Langhei complex in west central Minnesota (N. Lat. = 45 deg 41', W. Long. = 95 deg 43'). Historical tillage was primarily moldboard plow and disk harrow for the last 30 years. Soil C was measured at several depths at a 10-m spacing along east-west and north-south transects. Conventional moldboard plow (25 cm deep) and chisel plow (15 cm deep) equipment were used along the pre-marked transects. Gas exchange measurements utilized a large, portable chamber within 2 m of each sample site following tillage. The measured CO2 fluxes were largest with the moldboard plow > chisel plow > not tilled (before tillage). The variation in CO2 flux in the north-south transect was nearly four-fold immediately after plowing. The CO2 loss was only partially related to soil C with lower CO2 flux on the severely eroded sites. The CO2 loss partially reflected the degradation of soil properties as a result of wind and water erosion and tillage-induced soil translocation. The spatial variation of soil C across the landscape suggests non-point sources are complex. Therefore, conservation tillage methods need to be improved.