Effects of Potassium Fertilizer on Maize Growth and Heavy Metal Content in Heavy Metal Contaminated Soil

Pot test method is adopted in this study, and the corn is used as test material. In the soil contaminated by heavy metal As-CdPb-Cu, six different amounts of potassium fertilizer were used to treat the soil, which are No potassium, application of KCI 100 mg/kg, application of KCI 200 mg/kg, application of KCI 300 mg/kg, application of KCI 400 mg/kg, and application of KCI 500 mg/kg. It aims to study the effects of different potassium concentrations on the growth, absorption and accumulation of heavy metals (As, Cd, Pb and Cu) in corn seedlings. The results showed that different potassium concentrations promoted plant height, leaf width and root length of corn seedlings, but there was no significant difference compared with CK. Potassium fertilizer could significantly increase the absorption of heavy metals (As, Cd, Pb and Cu) by 2.4 times, 2.8 times, 2.3 times and 2.3 times, respectively. Among them, 200 mg/kg As, 300 mg/kg Cd, 200 mg/kg Pb and 200 mg/kg Cu were the best. The application of potassium fertilizer can reduce the absorption of As and Pb in the underground part of the maize, in which the content of As and Pb in the corn is the least with the concentration of 400 mg/kg. Potassium fertilizer could significantly increase the content of Cd and Cu, and the concentration of 20 and 100 mg/kg was respectively the best. Potassium fertilizer could reduce the contents of available heavy metals As, Cd and Cu in soil by 28.8, 14.4 and 7.9%, respectively, and at a maximum of 300, 500 and 500 mg/kg, respectively. Potassium fertilizer is beneficial to the increase of effective Pb content in soil, and the maximum increase is 200 mg/kg. Potassium fertilizer could promote the transfer ability and enrichment of heavy metals As, Cd, Pb and Cu in corn. The maximum transfer coefficients increased by 4.00 times, 47.6%, 3.11 times and 31.1%, respectively, and the treatment of 200, 300, 300 and 200 mg/kg was the highest respectively. The maximum enrichment coefficients were increased by 38.2%, 2.37 times, 74.5% and 2.23 times respectively, and 200, 300, 200 and 100 mg/kg was the highest respectively. There was a positive correlation between potassium application rate and heavy metal transfer coefficient and enrichment coefficient, and a very significant positive correlation between As transfer coefficient and Pb, Cu enrichment coefficient (C) 2020 Friends Science Publishers