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| Effects of biochar and calcium carbonate on cadmium accumulation and rhizosphere microbial communities in high- and low-cadmium accumulating rice cultivars |
| Received:March 21, 2022 Revised:April 25, 2022 |
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| KeyWord:heavy metal;cadmium contamination;passivator;rice;microbial community |
| Author Name | Affiliation | | TANG Zhong | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | ZHOU Ming | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | ZHANG Jun | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | ZHAO Fangjie | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China |
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| Abstract: |
| To study the inhibition effects of passivators on cadmium（Cd） accumulation in rice cultivars with different cadmium accumulation characteristics, pot experiments were performed to investigate the Cd accumulation in high- and low-Cd accumulating rice cultivars treated with two Cd passivators（biochar and calcium carbonate powder） . In addition, the effects of passivators on rhizosphere soil pH, available Cd content, and bacterial community structure of high- and low-Cd accumulating rice cultivars were investigated. Compared with the control, the application of calcium carbonate（CaCO3）could significantly increase the rhizosphere soil pH of the low- and high-Cd accumulating cultivar by 1.91 and 1.43, respectively, while the soil available Cd content decreased by 79.2% and 65.2%, respectively. The application of biochar significantly increased the rhizosphere soil pH of the low-Cd accumulating cultivar by 0.52 and decreased the soil available Cd content by 27%. No significant differences were observed for the rhizosphere soil pH and available Cd content of the high-Cd accumulating cultivar. Compared with the control, CaCO3 treatment decreased the Cd content in grains of low- and high-Cd accumulating cultivars by 91.8% and 88.1%, respectively. The application of biochar reduced Cd content in grains of low and high-Cd accumulating cultivars by 50.5% and 26%, respectively. The analysis of microbial community in rice rhizosphere soil at harvest time revealed that biochar mainly affected the abundance of bacterial community, while CaCO3 mainly affected the diversity of bacterial community. The collective findings indicate that application of CaCO3 was beneficial in decreasing Cd accumulation in both high - and low-Cd accumulating rice cultivars. The effect of biochar on decreasing Cd accumulation in low-Cd accumulating rice cultivars was better than that of in high-Cd accumulating rice cultivars. The combination of low-Cd accumulating rice cultivars and the application of CaCO 3 can be applied in medium and light Cd polluted acidic soils to ensure the safety of agricultural products. |
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