Soil organic carbon cycling in response to simulated soil moisture variation under field conditions

The combination of extended dry periods and high intensity rainfall, common in the southeastern US, leads to greater variability in soil moisture and consequently increases uncertainty to microbial processes pertinent to soil carbon (C) mineralization. However, field-based findings on soil moisture...

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Bibliographic Details
Published in:Scientific reports 2021-05, Vol.11 (1), p.10841-13, Article 10841
Main Authors: Singh, Shikha, Mayes, Melanie A., Shekoofa, Avat, Kivlin, Stephanie N., Bansal, Sangeeta, Jagadamma, Sindhu
Format: Article
Language:English
Subjects:
704/47
704/47/4113
Abundance
Agricultural land
biogeochemistry
Carbon cycle
Drought
ENVIRONMENTAL SCIENCES
Enzymatic activity
Enzymes
Glycine max
Humanities and Social Sciences
Mineralization
multidisciplinary
Organic carbon
Organic soils
Precipitation
Rainfall
Respiration
Science
Science (multidisciplinary)
Soil moisture
Soybeans
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Summary:The combination of extended dry periods and high intensity rainfall, common in the southeastern US, leads to greater variability in soil moisture and consequently increases uncertainty to microbial processes pertinent to soil carbon (C) mineralization. However, field-based findings on soil moisture sensitivity to soil C cycling are very limited. Therefore, a field experiment was conducted in 2018 and 2019 on a soybean ( Glycine max L.) cropland in the southeastern US with three soil moisture treatments: drought (simulated using rainout-shelter from June to October in each year), rainfed (natural precipitation), and irrigated (irrigation and precipitation). Soil respiration was measured weekly from May to November in both years. Soil samples were collected multiple times each year from 0–5, 5–15, and 15–30 cm depths to determine microbial biomass C (MBC), extractable organic C (EOC), hydrolytic enzyme activities, and fungal abundance. The cumulative respiration under drought compared to other treatments was lower by 32% to 33% in 2018 and 38% to 45% in 2019. Increased MBC, EOC, and fungal abundance were observed under drought than other treatments. Specific enzyme activity indicated fewer metabolically active microbes under drought treatment compared to rainfed and irrigated treatments. Also, maintenance of enzyme pool was observed under drought condition. These results provide critical insights on microbial metabolism in response to soil moisture variation and how that influences different pools of soil C under field conditions.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-021-90359-4