Submitted to: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting
Publication Type: Abstract Only
Publication Acceptance Date: November 12, 2006
Publication Date: November 12, 2006
Citation: Jabro, J.D., Sainju, U.M., Stevens, W.B., Evans, R.G. 2006. Soil carbon dioxide fluxes in relation to physical properties as influenced by management practices [CD-ROM]. Agronomy Abstracts. Indianapolis, Indiana: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting. 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 'v 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 = e' 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.