Nitrogen and potassium nutrients treatment have repair effect on arsenic pollution in paddy field, but till the date most of them are studied as a single element treatment. In this study, the hybrid rice Lu You Ming Zhan was used as the test material and paddy soil with different concentrations of arsenite addition, i.e. 0, 50 and 100 mg/kg arsenic, were prepared to investigate the mitigation effect of nitrogen and potassium combinely in arsenic toxicity, conventional cultivation condition of rice was used as the reference. The treatment group of this study consisted of 1.42 and 1.25 times of nitrogen and potassium respectively with respect to conventional cultivation conditions. The results showed that the concentration of total arsenic, arsenite and arsenate in rhizosphere soil solution were all significantly (p<0.01) decreased at tillering, botting, panicle initiation and ripening stage in above mentioned nitrogen and Potassium nutrition regulation group. The total amount of arsenic significantly (p<0.01) decreased in the mature rice roots, shoots, stems, leaves, bran and grain. The dry weight of rice roots, shoots, stems, leaves and rice yield was also significantly (p<0.01) increased. The combination of high nitrogen and high potassium nutrition has the best mitigation effect to As toxicity when the concentration of arsenite pollution was at 50 mg/kg. The repair effect in rice yield and dry weight of rice organs were also improved at 100mg/kg concentration of arsenite pollution. Therefore, nitrogen and potassium nutrients could effectively decrease the arsenic pollution in paddy soil and alleviate the arsenic toxicity on rice plants.

Funding support: Natural Science Foundation of China (grant numbers 21677033) and Fujian Provincial Project of Science and Technology (grant numbers 2017Y0002)