Effects of the combined regulation of nitrogen, phosphorus, and potassium nutrients on the migration and transformation of arsenic species in paddy soil.

Nitrogen (N), phosphorus (P) and potassium (K) are three macroelements in agriculture production, but their combined effects on arsenic (As) toxicity and its translocation in rice plants are not clear. In this study, an orthogonal rotation combination based on different N, P and K (NPK) concentration was first designed to examine their combined effect on the As toxicity, its transformation and migration in rice plants based on the hydroponic culture and pot soil culture. The results showed that 2.0 mg/L arsenite (As(III)) had obvious toxicity on the growth of indica LuYouMingZhan (LYMZ) and the optimal NPK concentration was 28.41, 6 and 50 mg/L based on the quadratic regression of the recovery rate of chlorophyll SPAD value of indica LYMZ. The optimal NPK combination significantly alleviated the physiological toxicity of As(III) on indica LYMZ rice seedling and decreased the accumulation of inorganic As in their roots and shoots by 23.8±1.8 % and 33.4±2.4 % respectively; further pot culture from different As(III) polluted soil showed that the optimal NPK combination significantly increased the dry weight of roots, stems, sheaths and leaves of indica LYMZ rice plants as well as yield indicators by 6.4 %-61.7 % and 7.1 %-89.8 % respectively, decreased the accumulation of As(III) and arsenate by 6.25 %-100 % and 12.36 %-100 % respectively in their roots, stems, sheaths, leaves, brans and kernels except As(III) concentration in their sheaths, decreased the accumulation of dimethylarsenate in their sheaths, leaves, brans and kernels, and had the best repair effect on the translocation of As species in 50 mg/kg As(III)-added soil. Our study provided a desirable strategy for alleviating As toxicity in paddy soil and reducing As pollution in rice plants.