| Rice is one of the important food. With the continuous improvement of quality of life, food safety issues are increasingly getting our attention. Passivating agent has the advantages of lower costs, wider range of applications, less impact in environment, etc., which has better applicability. In this paper, taking cadmium-polluted paddy fields at northwest area of guangxi province (L town、B town) and southeast area of guangxi province (S town) for the experimental plots, the demonstration of technology about passivating agent No.1 on the inhibition cadmium content in rice were studied, and the application of passivating agent to cadmium-polluted paddy fields control were discussed. The main results are as follows:First, different amounts of passivating agent No.1 applied to soil had different effects on pH. Studies showed that adding 250 kg/667 m2,500 kg/667 m2 and 1000 kg/667 m2 passivating agent to acidic soil at S town had a greater lifting effect on soil pH, from 5.33 of CK to 5.43、5.36 and 5.53, respectively, which pH was low. While it did not have the effect on soil pH for the neutral to slightly alkaline soil of northwest area of guangxi province (L town) test areas.Second, passivating agent could increase soil organic matter content, but did not reach significant level differences. For northwest area of guangxi province (L town) test areas, after adding 250 kg/667 m2,500 kg/667 m2 and 1000 kg/667 m2 passivating agent, soil organic matter content was 59.6 g·kg-1、57.8 g·kg-1 and 59.1 g·kg-1 respectively, applying in addition to the content of 500 kg/667 m2 processing was slightly lower than the control, In general,the use of passivating agent No.1 had an increasing tendency to soil organic matter content; for southeast area of guangxi province (S town) test areas, soil organic matter of CK was 29.1 g·kg-1. After treated the same with northwest area of guangxi province (L town), soil organic matter was 28.4 g·kg-1、 34.4 g·kg-1 and 33.3 g·kg-1 respectively, applying in addition to the content of 250 kg/667 m2 processing was slightly lower than the control, In general,the use of passivating agent No.1 had an increasing tendency to soil organic matter contentThird, passivating agent applied could decrease available cadmium content in soil. After the passivation agent applied 250 kg/667 m2,500 kg/667 m2 and 1000 kg/667 m2 into the lightly polluted farmland soil (southeast of guangxi S town), available content of soil cadmium by comparison of 0.215 mg/kg reduced to 0.202 mg/kg,0.187 mg/kg and 0.188 mg/kg, and in the 500 kg/667 m2 and 1000 kg/667 m2 with contrast difference significantly; for moderate pollution area (northwest guangxi L town) soil, soil available cadmium content under the same treatment by the contrast of 1.83 mg/kg to 1.816 mg/kg,1.734 mg/kg and 1.557 mg/kg, applying in the content of 1000 kg/667 m2 treatment, with significant difference. In heavy polluted area (northwest guangxi B town), application of passivator, available cadmium content by the contrast of 6.682 mg/kg reduced to 5.803 mg/kg, with significant difference.Fourth, the application of the passivating agent could reduce the cadmium content in rice, the effect of the applying in the content of 500 kg/667 m2 treatment was better. Light polluted farmland soil (southeast of guangxi S town) showed that treated with the different amount of passivating agent,250 kg/667 m2,500 kg/667 m2 and 1000 kg/667 m2, decreased the cadmium content from the control of 0.26 mg/kg to 0.13 mg/kg,0.12 mg/kg and 0.15 mg/kg respectively, compared with the control, which reached significant levels. In the moderate polluted test area (northwest guangxi L town), which treated as above mentioned, the cadmium concentration decreased from the control of 0.16 mg/kg to 0.15 mg/kg,0.098 mg/kg and 0.13 mg/kg respectively, the difference was not significant. In heavy polluted area (northwest guangxi B town), After application of passivating agent No.1, the cadmium concentration decreased from the control of 2.63 mg/kg to 1.75 mg/kg, compared with the control, the difference was significant.Fifth, the problems of the immobilization technology promotion process were summarized and combed, and the solutions were proposed. Combined with the Ministry of Agriculture project Demonstration of remediation of heavy metal pollution of agricultural products in Diaojiang River Basin, the key issues affecting the effect of technology promotion by combing and summarizing the problem encountered during the promotion of remediation technology were identified, such as the effect of the remediation technology, technical training of farmers, technology promotion during the technical support unit, the division of tasks in management units and technical collaboration units, and proposed solutions on the basis. Solutions were mainly:(1) to strengthen the government macro management, intensify policy support; (2) to speed up technology research and ripening; (3) to strengthen the construction of systems and mechanisms; (4) to improve the promotion team construction; (5) to update promotion way, to the new type of agricultural management main body; (6) enhancing the technical levels of farmers. Thesis research results for remediation of heavy metal pollution of farmland in guangxi, especially provides the reference for technical promotion. |
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