Comparing effects of ammonium and nitrate nitrogen on arsenic accumulation in brown rice and its dynamics in soil-plant system

• Published in: Journal of soils and sediments 2021-07, Vol.21 (7), p.2650-2658
• Main Authors: Zhang, Xin, Yang, Yongqiang, Fu, Qingling, Hu, Hongqing, Zhu, Jun, Liu, Manxia
• Format: Article
• Language: English
• Subjects: Accumulation; Agricultural production; Ammonium; Ammonium compounds; Ammonium nitrogen; Arsenic; Biomass; Dynamics; Earth and Environmental Science; Environment; Environmental Physics; Fertilizers; Iron; Nitrates; Nitrogen; Plaques; Pore water; Rice; Ripening; Sec 5 • Soil and Landscape Ecology • Research Article; Seedlings; Shoots; Soil; Soil contamination; Soil dynamics; Soil pollution; Soil Science & Conservation; Soils
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-021-02938-7

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.