Reduction in soil CO2 efflux through alteration of hydrothermal factor in milk vetch (Astragalus sinicus L.)-rapeseed (Brassica napus L.) intercropping system

Quan Zhou; Anna Gunina; Jiao Chen; Yi Xing; Ying Xiong; Zhiming Guo; Longchang Wang

doi:10.3389/fpls.2022.1093507

Reduction in soil CO₂ efflux through alteration of hydrothermal factor in milk vetch (Astragalus sinicus L.)-rapeseed (Brassica napus L.) intercropping system

Front Plant Sci. 2023 Jan 10:13:1093507. doi: 10.3389/fpls.2022.1093507. eCollection 2022.

Authors

Quan Zhou^{1

2

3}, Anna Gunina³, Jiao Chen¹, Yi Xing¹, Ying Xiong⁴, Zhiming Guo⁵, Longchang Wang¹

Affiliations

¹ College of Agronomy and Biotechnology, Southwest University/Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education/Engineering Research Center of South Upland Agriculture, Ministry of Education, Chongqing, China.
² Jiangxi Agricultural University/Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Nanchang, China.
³ Department of Environmental Chemistry, University of Kassel, Witzenhausen, Germany.
⁴ College of Agriculture, Henan University of Science and Technology, Luoyang, China.
⁵ Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.

Abstract

Introduction: Intercropping has a potential to reduce the CO₂ emission from farmlands. Limited information is available on the underlying reasons.

Methods: This study investigated the effect of milk vetch (Astragalus sinicus L.) (MV), rapeseed (Brassica napus L.) monoculture (RS) and intercropping (Intercrop) on soil CO₂ emissions, moisture and temperature in a bucket experiment during 210 days from October 2015 to May 2016 on Chongqing, China.

Results: The results showed that soil CO₂ efflux of MV, RS and Intercrop was 1.44, 1.55 and 2.08 μmol·m^-2·s^-1 during seedling and stem elongation stages and 3.08, 1.59 and 1.95 μmol·m^-2·s^-1 during flowering and podding stages. At seeding and stem elongation stages Intercrop had 1.4 times higher soil CO₂ efflux than the mean of MV and RS. In contrast, MVhad 1.6 times higher soil CO₂ efflux than Intercrop thereafter, which shows it was inhibited if milk vetch presents as Intercrop only. Decreased sensitivity of soil respiration to temperature in 1.4 times and lower soil moisture by Intercrop were found compared to MV. Intercrop decreased soil moisture, especially at the seedling and stem elongation stages, compared to the monoculture. The fluctuation on soil respiration in RS and Intercrop was slight with changes in soil moisture.

Conclusion: Thus, milk vetch-rapeseed system has a potential to decrease CO₂ emission from farmland, however soil moisture should be regulated properly.

Keywords: SOM balance; greenhouse gas emission; legume-brassica intercrops; soil moisture; soil temperature.

Grants and funding

This study was financially supported by the National Natural Science Foundation of China (31901476, 31871583, 31271673), the Jiangxi Provincial Natural Science Foundation (20202ACBL215002), the Special Fund for Agro-scientific Research in the Public Interest (201503127) and China Scholarship Council (CSC).