| Effect of green manure cover cropping on soil aggregate\|associated organic carbon in a dryland winter wheat field |
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| DOI：10.7606/j.issn.1000-7601.2023.03.27 |
| Key Words: green manure cover cropping soil aggregate soil organic carbon particle organic carbon |
| Author Name | Affiliation | | LI Chao | College of Urban and Environmental Science, Northwest University, Xi’an, Shaanxi 710127, China
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Xi’an, Shaanxi 710127, China | | WANG Jun | College of Urban and Environmental Science, Northwest University, Xi’an, Shaanxi 710127, China
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Xi’an, Shaanxi 710127, China
Institute of Water and Soil conservation Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China | | WEN Mengmeng | College of Urban and Environmental Science, Northwest University, Xi’an, Shaanxi 710127, China
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Xi’an, Shaanxi 710127, China | | ZHANG Shaohong | College of Urban and Environmental Science, Northwest University, Xi’an, Shaanxi 710127, China
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Xi’an, Shaanxi 710127, China | | XING Wenchao | College of Urban and Environmental Science, Northwest University, Xi’an, Shaanxi 710127, China
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Xi’an, Shaanxi 710127, China | | FU Xin | College of Land and Resources, Hebei Agricultural University, Baoding, Hebei 071001, China |
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| Abstract: |
| Based on a 4-year field experiment in the Loess Plateau, the effects of green manure cover cropping on soil aggregates and aggregate\|associated organic carbon were studied. Three cover crops including Changwu soybean (SB), Sudan grass (SG), Changwu soybean/Sudan grass mixture (Mix) and a control with no cover crop (CK) were set during summer fallow period under winter wheat monoculture. Dry sieving method was used to sieve the whole soil into >5 mm, 2~5 mm, 0.25~2 mm and <0.25 mm size class for soil aggregation measurements. The contents of organic carbon and particulate organic carbon in the soil and each size class aggregate, aggregate mean weight diameter and contribution of soil organic carbon were determined separately. The results showed that cover cropping had a significant effect on soil aggregates distribution. Cover crop enhanced the formation of soil aggregates at 0~10 cm soil layer but had little impact on subsoils. Compared to CK, SB, SG and Mix significantly increased soil organic carbon content, particulate organic carbon content and aggregate mean weight diameter at 0~40 cm depths by 7.9%, 8.0% and 7.9%, respectively. SB group was more beneficial to soil carbon sequestration in the surface layer than SG and Mix. Soil organic carbon content and particulate organic carbon content showed a significant positive correlation, both of which had a significant negative correlation with aggregate mean weight diameter. The contents of aggregate\|associated organic carbon varied with cover crop treatments and soil depths. Compared with CK, SB and Mix significantly increased the contents of organic carbon and particulate organic carbon at 0~10 cm, and SG increased soil organic carbon content at 10~20 cm. Although <0.25 mm aggregates had a greater aggregate\|associated organic carbon content than other size classes, more than 80% of organic carbon fractions in aggregates was from >0.25 mm aggregate. In addition, cover cropping increased the contributions of >5 mm aggregate\|associated organic carbon and particulate organic carbon, indicating organic carbon were sequestrated in the >5 mm aggregates with cover crops. In conclusion, planting cover crops especially Changwu soybean effectively improved soil carbon storage and promoted the distribution and retention of aggregate organic carbon pool in the dry farming area of the Loess Plateau. |
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