Yao Shuhua, Yang Dan, Zhang Xuexia, Shi Lei, Zhang Xiaoxia
Liaoning Engineering Research Center for Treatment and Recycling of Industrially Discharged Heavy Metals, Shenyang University of Chemical Technology, Shenyang 110142, China.
National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
Life (Basel). 2022 Oct 4;12(10):1541. doi: 10.3390/life12101541.
Nitrogen (N) fertilizer affects the migration and transformation of arsenic (As) in soil and rice. We conducted pot experiments and studied the effects of 0.1, 0.2, and 0.4 g∙kg−1 N levels of NH4Cl, (NH4)2SO4, and NH4NO3 fertilizers on the As bioavailability in the As-contaminated inter-rhizosphere soil and As accumulation in the rice organs. The results showed that the concentration of bioavailable As in the rice rhizosphere soil was significantly negatively correlated with pH under the 0.4 g∙kg−1 N level of each fertilizer. At the same N level, while the As concentration was maturity stage > tillering stage in rice stems and leaves treated with NH4Cl and (NH4)2SO4, it was the opposite in roots. This suggests that the transfer of As from roots to stems and leaves mainly occurs in the late stage of rice growth under the condition of only NH4+-N fertilizer applying. The As concentration in rice aboveground organ (grains and stems−leaves) decreased with the increasing N application under the same N fertilizer treatment condition during the mature stage. In addition, the As concentration in rice grains treated with (NH4)2SO4 was the lowest. This result indicated that SO42− and NH4+-N had a significant synergistic inhibition on the As accumulation in rice grains. It was concluded that appropriate (NH4)2SO4 levels for As-contaminated paddy soils with high sulfur (S) contents would obtain rice grains with inorganic As concentrations below 0.2 mg·kg−1.
氮肥影响土壤和水稻中砷（As）的迁移和转化。我们进行了盆栽试验，研究了0.1、0.2和0.4 g∙kg−1氮水平的氯化铵、硫酸铵和硝酸铵肥料对砷污染根际间土壤中砷的生物有效性以及水稻各器官中砷积累的影响。结果表明，在每种肥料0.4 g∙kg−1氮水平下，水稻根际土壤中生物可利用砷的浓度与pH值呈显著负相关。在相同氮水平下，用氯化铵和硫酸铵处理的水稻茎叶中砷浓度在成熟期>分蘖期，而在根中则相反。这表明在仅施用铵态氮肥的条件下，砷从根向茎叶的转移主要发生在水稻生长后期。在相同氮肥处理条件下，成熟期水稻地上部器官（谷粒和茎叶）中的砷浓度随施氮量增加而降低。此外，用硫酸铵处理的水稻谷粒中砷浓度最低。这一结果表明，硫酸根离子和铵态氮对水稻籽粒中砷的积累具有显著的协同抑制作用。得出的结论是，对于硫含量高且受砷污染的稻田土壤，适当的硫酸铵水平可使水稻籽粒中无机砷浓度低于0.2 mg·kg−1。
