Effects of Biochar Application on Soil Organic Carbon Composition and Enzyme Activity in Paddy Soil under Water-Saving Irrigation

Shihong Yang, Xi Chen, Zewei Jiang, Jie Ding, Xiao Sun and Junzeng Xu
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Shihong Yang: State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China
Xi Chen: College of Agricultural Engineering, Hohai University, Nanjing 210098, China
Zewei Jiang: College of Agricultural Engineering, Hohai University, Nanjing 210098, China
Jie Ding: College of Agricultural Engineering, Hohai University, Nanjing 210098, China
Xiao Sun: College of Agricultural Engineering, Hohai University, Nanjing 210098, China
Junzeng Xu: State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China

IJERPH, 2020, vol. 17, issue 1, 1-17

Abstract: Rice water-saving irrigation technology can remarkably reduce irrigation water input and maintain high yield; however, this technology can also accelerate the decomposition of soil organic matter in paddy fields. The spatial and temporal distributions of soil organic carbon (SOC), water-soluble organic carbon (WSOC), and soil microbial biomass carbon (SMBC) under different water-carbon regulation scenarios were analyzed on the basis of field experiments in the Taihu Lake region in China to explore the effects of biochar application on SOC and its components in water-saving irrigation paddy fields. The response of soil catalase (CAT) and invertase (INV) to biochar application in water-saving irrigated rice fields was clarified. The results showed that water-saving irrigation reduced the SOC content by 5.7% to 13.3% but increased WSOC and SMBC contents by 13.8% to 26.1% and 0.9% to 11.1%, respectively, as compared with flooding irrigation. Nonflooding management promoted the oxidative decomposition of soil organic matter. Two years after straw biochar was added, paddy soil SOC content under water-saving irrigation was increased by 4.0% to 26.7%. The WSOC and SMBC contents were also increased by 4.0% to 52.4% and 7.0% to 40.8%, respectively. The high straw biochar addition rate exhibited great impact on SOC. Remarkable correlations among SOC, WSOC, and SMBC were observed, indicating that the addition of straw biochar improved soil labile C, such as WSOC and SMBC, which promoted SOC transformation and stability in paddy soil under water-saving irrigation. Soil CAT and INV were related to SOC conversion. In conclusion, the combination of water-saving irrigation and straw biochar addition was beneficial to the improvement of soil properties and fertility of paddy fields.

Keywords: paddy fields; straw biochar; water-saving irrigation; soil organic carbon; soil enzyme activity (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

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