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| Effects of green manure crops on cadmium availability in dryland soils in Yunnan, China |
| Received:April 16, 2021 |
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| KeyWord:green manure;cadmium;availability;dissolved organic matter |
| Author Name | Affiliation | E-mail | | WANG Yun | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | FU Libo | Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming 650205, China | | | LIANG Hai | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | ZHANG Zihan | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | YANG Wei | Kunming Agricultural Products Quality and Safety Center, Kunming 650118, China | | | HE Zhenghai | Agricultural and Rural Bureau of Funing Country, Funing 663400, China | | | GAO Songjuan | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | gaosongjuan@njau.edu.cn | | CAO Weidong | Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China | caoweidong@caas.cn |
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| Abstract: |
| This study investigated the impact of different green manure crops on the availability, absorption and transportation of cadmium (Cd)in moderately Cd-contaminated soil(average total Cd content=1.21 mg·kg-1), to provide theoretical support to green manure-based soil safety production methods in Yunnan dryland. A pot experiment was used to carry out this investigation; the experiment consisted of eight treatments, including seven types of winter green manure crops(i.e., Chinese milk vetch, hairy vetch, common vetch, smooth vetch, February orchid, rape, ryegrass), and winter fallow as the control. Soils and plants were sampled during the full bloom stage and the same stage as the green manures. The soil physico-chemical properties, Cd availability, and the Cd content in the roots and shoots of the green manures were measured; then, the bioconcentration and translocation factors of green manures were calculated. Compared with the control, the soil dissolved organic carbon(DOC) content of the Chinese milk vetch and ryegrass treatments increased by 29.3% and 33.7%, respectively. The seven green manure crops all significantly reduced available soil Cd content, in which the available Cd in the soil treated with common vetch, smooth vetch, and ryegrass decreased by 32.1%, 29.2%, and 33.0%, respectively. The total Cd in soil treated with Chinese milk vetch, hairy vetch, common vetch, and smooth vetch decreased by 45.4%, 34.9%, 34.5%, and 33.2%, respectively. The four types of leguminous green manure mainly accumulated Cd in the roots, and the bioconcentration and translocation factors were lower than the other legume types. The Cd in the gramineous and cruciferous green manures was mainly concentrated in the shoots, and the bioconcentration and translocation factors were significantly higher than the leguminous green manure. Among them, the bioconcentration factor of the February orchid was the highest(0.813), and the translocation factor of rape was the highest(0.772). Soil nutrients had significant positive impacts on the available soil Cd, whereas DOC had a relatively significant negative impact on the Cd content of plant shoots. This indicates that an increase in DOC content may reduce the Cd content of plants. Planting leguminous green manure, particularly smooth vetch, improves soil nutrients and quality and reduces the soil available Cd content with a lower bioconcentration factor and translocation factor. |
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