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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGICALLY-SOUND PEST, WATER AND SOIL MANAGEMENT STRATEGIES FOR NORTHERN GREAT PLAINS CROPPING SYSTEMS

Location: Agricultural Systems Research Unit

Title: Land Use and Management Practices Impact on Plant Biomass Carbon and Soil Carbon Dioxide Emission

Authors
item Sainju, Upendra
item Stevens, William
item Caesar, Thecan
item Jabro, Jalal "jay"

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 24, 2010
Publication Date: August 12, 2010
Repository URL: http://hdl.handle.net/10113/47842
Citation: Sainju, U.M., Stevens, W.B., Caesar, T., Jabro, J.D. 2010. Land use and management practices impact on plant biomass carbon and soil carbon dioxide emission. Soil Science Society of America Journal. 74(5):1613-1622.

Interpretive Summary: Carbon dioxide, a major greenhouse gas responsible for global warming, is emitted from crop- and grasslands due to oxidation of soil organic matter, root and microbial respiration, and return of nonharvestable plant residue in the soil. In contrast, soil is also an important sink of atmospheric CO2 which is absorbed by plant biomass through photosynthesis and converted into soil organic matter after the plant residue is returned to the soil. The balance between the amounts of plant residue C (fixed through photosynthesis) added to the soil and rate of C mineralized as CO2 emission determines the level of soil C storage. Little is known about the influence of land use and management practices on soil CO2 emission in the northern Great Plains. We evaluated the effect of a combination of irrigation, tillage, cropping system, and N fertilization on plant biomass (leaves + stems) C, soil temperature and water content at the 0- to 15-cm depth, and CO2 emission in a Lihen sandy loam under crops and grasses from April to October, 2006 to 2008 in western North Dakota. Treatments were two irrigation practices (irrigated and non-irrigated) and six cropping systems [conventional-tilled malt barley with N fertilizer (CTBFN), conventional-tilled malt barley with no N fertilizer (CTBON), no-tilled malt barley-pea with N fertilizer (NTB-PN), no-tilled malt barley with N fertilizer (NTBFN), no-tilled malt barley with no N fertilizer (NTBON), and no-tilled Conservation Reserve Program (grassland) (NTCRP)]. Plant biomass C was greater in NTBFN than in NTBON in 2006 and 2007 but was greater in NTB-PN than in CTBON, NTBON, and NTCRP in 2008. Similarly, biomass C was greater with the irrigated than with the non-irrigated practice, greater with N fertilization than without, and greater with crops than with grasses. Soil temperature was greater but water content was lower in NTCRP than in CTBFN and NTBFN. Soil CO2 flux varied with time of measurement, peaking immediately following heavy rain or irrigation (>15 mm). Total CO2 flux from April to October was greater in the irrigated than in the non-irrigated practice and greater in NTCRP than in other cropping systems. Similarly, the flux was greater with tillage than without in 2007 and 2008 but lower with N fertilization than without in 2007. Soil CO2 emission was probably related more to increased microbial activity due to increased soil temperature and water content or tillage practice than to aboveground plant C input. Greater root respiration probably increased CO2 emission with perennial grasses compared with annual crops.

Technical Abstract: Land use and management practices may influence plant C input and soil CO2 emission, a greenhouse gas responsible for global warming. We evaluated the effect of a combination of irrigation, tillage, cropping system, and N fertilization on plant biomass (leaves + stems) C, soil temperature and water content at the 0- to 15-cm depth, and CO2 emission in a Lihen sandy loam (sandy, mixed, frigid, Entic Haplustolls) under crops and grasses from April to October, 2006 to 2008 in western North Dakota. Treatments were two irrigation practices (irrigated and non-irrigated) and six cropping systems [conventional-tilled malt barley (Hordeum vulgaris L.) with N fertilizer (CTBFN), conventional-tilled malt barley with no N fertilizer (CTBON), no-tilled malt barley-pea (Pisum sativum L.) with N fertilizer (NTB-PN), no-tilled malt barley with N fertilizer (NTBFN), no-tilled malt barley with no N fertilizer (NTBON), and no-tilled Conservation Reserve Program (grassland) (NTCRP)]. Plant biomass C was greater in NTBFN than in NTBON in 2006 and 2007 but was greater in NTB-PN than in CTBON, NTBON, and NTCRP in 2008. Similarly, biomass C was greater with the irrigated than with the non-irrigated practice, greater with N fertilization than without, and greater with crops than with grasses. Soil temperature was greater but water content was lower in NTCRP than in CTBFN and NTBFN. Soil CO2 flux varied with time of measurement, peaking immediately following heavy rain or irrigation (>15 mm). Total CO2 flux from April to October was greater in the irrigated than in the non-irrigated practice and greater in NTCRP than in other cropping systems. Similarly, the flux was greater with tillage than without in 2007 and 2008 but lower with N fertilization than without in 2007. Soil CO2 emission was probably related more to increased microbial activity due to increased soil temperature and water content or tillage practice than to aboveground plant C input. Greater root respiration probably increased CO2 emission with perennial grasses compared with annual crops.

Last Modified: 7/30/2014
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