Land Use and Management Practices Impact on Plant Biomass Carbon and Soil Carbon Dioxide Emission
2010
Sainju, Upendra M. | Stevens, William B. | Caesar-TonThat, Thecan | Jabro, Jalal D.
Land use and management practices may influence plant C inputs and soil CO₂ emission. We evaluated the effect of a combination of irrigation, tillage, cropping system, and N fertilization on plant biomass C, soil temperature and water content at the 0- to 15-cm depth, and CO₂ emission in a sandy loam soil from April to October, 2006 to 2008, in western North Dakota. Treatments were two irrigation practices (irrigated and unirrigated) and six cropping systems (conventional-tilled malt barley [Hordeum vulgare 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 [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, or NTCRP in 2008. Soil temperature was greater but water content was lower in NTCRP than in CTBFN and NTBFN. Soil CO₂ flux peaked immediately following heavy rain or irrigation (>15 mm). Total CO₂ flux from April to October was greater in the irrigated than in the unirrigated practice and greater in NTCRP than in annual cropping systems. Soil CO₂ emission was probably related more to soil temperature and water content or tillage than to aboveground plant C input. Because of reduced CO₂ flux compared with CTBON and NTCRP but similar biomass yield as NTBFN and CTBFN, NTB-PN may be used to reduce CO₂ emission from croplands in the northern Great Plains.
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