Purpose

Nitrogen is widely used in agricultural production, including in arsenic-contaminated soil. However, there is a lack of systematic studies on the arsenic (As) dynamics in soil porewater–root surface–rice system after applying different nitrogen fertilizers to As-contaminated soil.

Materials and methods

Three treatments (CK, Nitrate-N, and Ammonium-N) were applied before rice planting to investigate the effect of nitrogen forms on arsenic accumulation in brown rice and its dynamics in soil-plant system.

Results and discussion

Compared to Nitrate-N and CK treatments, Ammonium-N treatment increased rice biomass and yield. Compared with CK treatment (0.12 and 4.48 mg/kg), Ammonium-N treatment (0.08 and 2.71 mg/kg) reduced the As concentrations and Nitrate-N treatment (0.18 and 6.20 mg/kg) increased the As concentrations in brown rice and shoots. Nitrogen application reduced Fe plaques concentration on roots, but Ammonium-N treatment increased the total As accumulation in Fe plaques. In soil porewater, Nitrate-N treatment reduced the concentration of As (III) in the first month (5.2–47.0 μg/L) but increased its concentration in the last month (137.6–183.1 μg/L). However, the concentration of As (III) in Ammonium-N treatment (58.5–168.6 μg/L) was similar to that in CK treatment (72.8–138.8 μg/L) in porewater.

Conclusions

The application of Nitrate-N caused the decrease of As in porewater during the seedling stage; however, the As concentration in rice grains was increased due to the increase of As (III) in porewater during the ripening stage. The application of Ammonium-N reduced the As concentration in rice tissues by increasing biomass and accumulating more As in Fe plaques.

中文翻译：

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铵态氮和硝态氮对糙米砷积累的影响及其在土壤-植物系统中的动态比较

目的

氮广泛用于农业生产，包括在受砷污染的土壤中。然而，对As污染土壤施用不同氮肥后土壤孔隙水-根面-水稻系统中砷（As）的动态变化缺乏系统研究。

材料和方法

在水稻种植前应用三种处理（CK、硝酸盐-N 和铵-N）来研究氮形式对糙米砷积累的影响及其在土壤-植物系统中的动态。

结果和讨论

与硝酸盐-N 和 CK 处理相比，铵-N 处理增加了水稻生物量和产量。与 CK 处理（0.12 和 4.48 mg/kg）相比，Ammonium-N 处理（0.08 和 2.71 mg/kg）降低了砷浓度，而硝酸盐处理（0.18 和 6.20 mg/kg）增加了糙米和糙米中的砷浓度。射击。施氮降低了根上铁斑块的浓度，但氨氮处理增加了铁斑块中总砷的积累。在土壤孔隙水中，硝酸盐-N 处理在第一个月降低了 As (III) 的浓度 (5.2–47.0 μg/L)，但在最后一个月增加了其浓度 (137.6–183.1 μg/L)。然而，Ammonium-N 处理中 As (III) 的浓度（58.5-168.6 μg/L）与孔隙水中的 CK 处理（72.8-138.8 μg/L）相似。

结论

Nitrate-N的施用导致苗期孔隙水中As的减少；然而，由于成熟阶段孔隙水中 As (III) 的增加，水稻籽粒中的 As 浓度增加。铵态氮的施用通过增加生物量和在铁斑块中积累更多的砷来降低水稻组织中的砷浓度。