In this study, we conducted a laboratory experiment to study the effects of oxygen-loaded biochar on nitrogen transformation and arsenic migration in paddy soil, and to assess the inhibition effect of oxygen-loaded biochar on arsenic migration in paddy soil-rice system. The results showed that the oxygen-loaded walnut shell biochar reduced the pH of pore water, alleviated the decline of DO and increased Eh. Meanwhile, the abundance of amoA gene in the paddy soil significantly increased(P<0.05), which promoted the nitrification process. Also the the release of nitrous oxide was reduced and the loss of total nitrogen was depressed. After 80days, the arsenic(III)content in the paddy soil in the oxygen-loaded biochar and biochar applied treatment accounted for 42.6%、51.9%, respectively, which were significantly lower(P<0.05)than that in control(90.2%). The amendment of oxygen-loaded biochar was also responsible for the increase in the height and tillers of rice, as well as the accumulation of iron plaque around rice root, which reached 18.4 mg/kg and was 4.2 times higher than that in control. Therefore, the arsenic content in rice was reduced by 46.3%. This indicates that the addition of oxygen-loaded biochar in paddy soil increased the concentration of iron plaque in rice roots, led to more arsenic fixation, and triggered the reduction in the accumulation of arsenic in rice. The results offer a new sight to inhibit the nitrogen loss in paddy soil and arsenic mitigation in rice.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |