Mitigation Of Cadmium Accumulation In Rice And Rape By Amendments In Contaminated Arable Soils

In order to explore the application potential of different modifiers for the treatment of cadmium (Cd) contaminated soil, four types of soil modifiers including of mineral silicon fertilizer, silicon calcium magnesium potash fertilizer, spraying with silicon fertilizer and microbial agents for soil conditioner were added to Cd contaminated soil with different Cd concentration (combined and single Cd contaminated soil) using rice and rape outdoor pot experiment method and the effect of soil modifiers on the absorption and accumulation of the Cd by the rice, rapeseed were investigated. Moreover, effect of mineral silicon fertilizer, microbial agents, two kinds of equipping fertilization and flooded measures on the cadmium accumulation in the rice were investigated by field randomized block experiment at Cd polluted paddy fields in zhuzhou city chaling magan, dongxiang and chung town township. The results obtained here will provide scientific basis for control of Cd pollution in rice in hunan province. The main results are as follows:(1) Effect of mineral silicon fertilizer, silicon calcium magnesium potash fertilizer, microbial agents and combined application of these soil modifiers on the cadmium accumulation in the late rice and early ricrice were investigated by outdoor pot experiments on the single cadmium polluted soil..Almoset all treatments can obviously decrease Cd content in the roots, leaf sheaths, leaf and chaff in brown rice except that the silicon calcium magnesium potash fertilizer (Gsi) treatment have no obvious effect on Cd accumulation in some parts of the plant, as compared to CK, through outdoor pot experiment at single Cd contaminated soil. Among the all the soil modifiers, the microbial agents (F) were donmenstrated as the most effective on the reduction of Cd accumulation in the rice, with a reducing efficiency of 55.31% and 69.37% respectively. The spraying with silicon fertilizer (Ysi) and mineral silicon fertilizer+microbial agents (Ksi+F) were shown a good performance on reducing Cd accumulation in the leaf of the rice. Rice yield, compared with CK, different treatment all can increase rice yield to some extent and the highest yield was obtained by the Ksi+F treatment.(2) Effect of mineral silicon fertilizer, silicon calcium magnesium potash fertilizer, microbial agents and combined application of these soil modifiers on the Cd accumulation in the late rice and early ricrice were investigated by outdoor pot experiments on the combined cadmium polluted soil. Almoset all treatments can obviously decrease Cd content in the roots, leaf sheaths, leaf and chaff in brown rice except that the Gsi treatment have no obvious effect on Cd accumulation in some parts of the plant, as compared to CK, through outdoor pot experiment at single Cd contaminated soil. Among the all the soil modifiers, the F were donmenstrated as the most effective on the reduction of Cd accumulation in the rice, with a reducing efficiency of 52.96% and 39.76% respectively. The Ysi and Ksi+F were shown a good performance on reducing Cd accumulation in the leaf of the rice. Rice yield, compared with CK, different treatment all can increase rice yield to some extent and the highest yield was obtained by the Ksi+F treatment.(3) Effect of application of mineral silicon fertilizer application, silicon calcium magnesium potash fertilizer, microbial agents and equipping applied for two seasons rice (early rice and late rice) on cadmium accumulation in the rapeseed seedling stage and mature stage canola plants were investigated by outdoor potted experiment on Cd contaminated soil with three different comtamintion level. The total quantity of Cd in soil, effective state of Cd and the cadmium content in different parts of the rice were measured. Compared with CK, different treatments can effectivly reduce the Cd content in the any part of the rape at its seedling stage and mature stage. the Ksi and F were donmenstrated as the most effective on the reduction of Cd accumulation in the rape, with a reducing efficiency of 40.12% and 44.22%respectively. The cadmium content in the stem sheath, leaf, chaff and brown rice were lower in the EerJiDao than in the YiJiDao other than in the root(4) Effect of application of mineral silicon fertilizer, silicon calcium magnesium potash fertilizer, microbial agents, combined application of these soil modifiers and flooded measures on the Cd accumulation in two seasons rice (early rice and late rice) were investigated by field randomized block experiment on the soil with three different levels of Cd contamination. Compared with CK, different treatments can effectivly reduce the Cd content in the any part of the brown rice. The Ksi and F treatment was donmenstrated more effective on the reduction of Cd accumulation than other treatmtments, with a reducing efficiency of 32.53%?48.11% and 49.46%, respectively, which can meet the national safety standards for rice (Cd< 0.2 mg/kg).Moreover, the Cd content in the early rice and the brown rice from lightly and heavily polluted area can also be decreased to below the national safety standards for Cd in the rice. The Ksi treatment show the best performance on reducing Cd accumulation in three groups of brown rice, with a reducing efficiency of 21.74%,24.32% and 21.74% respectively and only F and Ksi treatment can reducing the Cd content in brown rice in lightly Cd polluted area below the national safety standards for Cd in the rice. Compared with CK, different treatment all can improve rice production to some extent and the highest yield was achived by the Ksi+ F treatment.