Soil Carbon Pools in Dryland Agroecosystems as Affected by Several Years of Drought.

Autor: Sherrod LA, McMaster GS, Delgado JA, Schipanski ME, Fonte SJ, Montenieri RL, Larson K
Jazyk: angličtina
Zdroj: Journal of environmental quality [J Environ Qual] 2018 Jul; Vol. 47 (4), pp. 766-773.
DOI: 10.2134/jeq2017.09.0371
Abstrakt: No-till and increased cropping intensity (CI) can increase yield and soil organic C (SOC) in the US Great Plains compared with traditional wheat ( L.)-fallow management. However, gains in SOC and other C pools may not be permanent. Increasing frequency of drought may reduce C inputs and potentially reverse gains accrued during wetter periods. This study examined the effect of drought on the persistence of SOC with two objectives: (i) to determine soil C pools (0-20 cm) after 24 yr in no-till as influenced by potential evapotranspiration (PET), landscape position (slope), and CI; and (ii) to compare the size of the C pools after the first 12 yr (wet) versus the subsequent 12 yr, notable for frequent droughts. Rotations were wheat-corn ( L.)-fallow (WCF), continuous cropping (CC), and a grass Conservation Reserve Program mixture planted across slopes at three sites in Colorado with similar precipitation but increasing PET. After 24 yr, water-soluble organic C increased with CI from WCF to CC to grass with 250, 340, and 440 kg C ha, respectively. Soil microbial biomass C also increased with CI-1500, 1660, and 2135 kg C ha for WCF, CC, and grass, respectively. The particulate organic matter C pool had a three-way interaction with PET, slope, and CI. Overall, between Years 12 and 24, SOC increased in grass by 16.9%, with a rate of 425 kg C ha yr sequestration compared with 10.5 and 1.4% for the WCF and CC systems, respectively.
(Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.)
Databáze: MEDLINE
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