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United States Department of Agriculture

Agricultural Research Service

Title: Carbon dioxide flux as affected by tillage and irrigation in soil converted from perennial forages to annual crops

Authors
item Jabro, Jalal "jay"
item Sainju, Upendra
item Stevens, William
item Evans, Robert

Submitted to: Journal of Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 18, 2007
Publication Date: August 22, 2007
Repository URL: http://hdl.handle.net/10113/20297
Citation: Jabro, J.D., Sainju, U.M., Stevens, W.B., Evans, R.G. 2008. Carbon dioxide flux as affected by tillage and irrigation in soil converted from perennial forages to annual crops. Journal of Environmental Management. 88: 1478-1484.

Interpretive Summary: The CO2 flux, soil temperature (Ts), volumetric soil water content (MC) were measured every 1 to 2 wk in no-till (NT) and conventional till (CT) malt barley and undisturbed soil grass-alfalfa (UGA) systems in a Lihen sandy loam soil (sandy, mixed, frigid Entic Haplustoll) under irrigated and non-irrigated conditions in western North Dakota. Soil air-filled porosity (E) was calculated from total soil porosity and 'v measurements. Significant differences in CO2 fluxes between land management practices (irrigation and tillage) were observed on some measurement dates. Irrigation increased carbon dioxide (CO2) emission from the soil surface to the atmosphere and therefore reduces the amount of C sequestered by the soil. Furthermore, increasing soil temperature was accompanied by increasing soil CO2 fluxes. A positive, high correlation was found between soil temperature and the CO2 emission from the soil surface, which was well described by an exponential function. Conventional tillage (CT) of malt barley leads to higher levels of CO2 fluxes that were significantly different from both no-till (NT) malt barley and undisturbed grass-alfalfa (UGA) treatments. However, there were no significant differences with respect to soil CO2 emission between NT and UGA treatments. The results suggest that adopting less intensive tillage such as no-till or strip tillage will prove remarkably effective in reducing soil CO2 evolution, thus increasing C sequestration in the soil. Furthermore, adopting the practice of irrigating less frequently without compromising crop productivity and quality will reduce the CO2 evolution from the soil environment to the atmosphere.

Technical Abstract: Among greenhouse gases, carbon dioxide (CO2) is one of the most significant contributors to regional and global warming as well as climatic change. However, CO2 flux from the soil surface to the atmosphere can be affected by modifications in soil physical properties resulting from changes in land management practices. The CO2 flux, soil temperature (Ts), volumetric soil water content (MC) were measured every 1 to 2 wk in no-till (NT) and conventional till (CT) malt barley and undisturbed soil grass-alfalfa (UGA) systems in a Lihen sandy loam soil (sandy, mixed, frigid Entic Haplustoll) under irrigated and non-irrigated conditions in western North Dakota. Soil air-filled porosity (E) was calculated from total soil porosity and MC measurements. Significant differences in CO2 fluxes between land management practices (irrigation and tillage) were observed on some measurement dates. Higher CO2 fluxes were detected in CT plots than in NT and UGA treatments immediately after rainfall or irrigation. Soil CO2 fluxes increased with increasing soil moisture (R2 = 0.15, P<0.01) while an exponential relationship was found between CO2 emission and Ts (R2 = 0.59). Using a stepwise regression analysis procedure, a significant multiple regression equation was developed between CO2 flux and MC, Ts (CO2 flux = exp 3.477 + 0.123Ts + 6.381MC; R2 = 0.68, P = 0.01). Not surprisingly, soil temperature was a driving factor in the equation, which accounted for approximately 59% in variation of CO2 flux. It appears that soil CO2 flux is a function of soil temperature and water content due to changes in land management practices.

Last Modified: 10/20/2014
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