Study On The Safe Production Of Cadmium In Rice Regulated By Soil Conditioner And Water Status In Chengdu Plain Region

The soil pollution of cultivated land is increasing with the rapid development of industry and agriculture.Southwest of China has become one of the lage contaminated areas heavy metal Cd pollution in Chengdu plain area is a typical representative.The fertile soil in Chengdu plain area has been an important source of rice supply in Sichuan and Chongqing areas for a long time.However,this area is plagued by soil heavy metal Cd pollution,leading to part of the rice with excessive content of Cd.If there was no feasible soil heavy metal Cd pollution control action carried out,it will affect the quality of rice and endanger the health of the people in this region.Based on the gravity of the Cd pollution,the necessity of management work in the Chengdu plain and combine with the previous research discovers,this study carried out soil conditioner passivation effect experiment and water management regulation.It also carried out the typical regional governance effect of technology integration reaserch by using the low Cd accumulation rice in Chengdu plain with Cd pollution.The main results were as follows:(1)The biochar,bacterial residue,modified sepiolite and mixed conditioner could effectively reduce the Cd content and Cd accumulation of rice.Compared with single conditioner raw material,the mixed conditioner at the same dosage showed better ability to prevent and control soil Cd pollution.When the dosage of mixed conditioner is 200 kg/mu,the mixed conditioner can reduce the Cd content of ordinary Yixiangyou 2115 brown rice by 34.7%,and the Cd content of rice cultivar Chuanyou 6203 brown rice by 37.5%.In addition,the content of Cd in Chuanyou 6203 brown rice was only 0.193 mg/kg,below the national standard(0.2 mg/kg)for food safety with the condition of applying 200 kg/mu of mixed conditioner.(2)Compared with conventional water management measures in agricultural production,keeping the field wet or flooded could effectively reduce the content of Cd in rice.The Cd content and Cd accumulation in each organ of rice decreased the most when the water was flooded during the whole growth period.The content of Cd in brown rice of Yixiangyou 2115 was 36% lower than that of the conventional water management measures.Cd content of Chuanyou 6203 brown rice was 28% which is lower than that of conventional water management measures.(3)when compared with the single prevention and control measures of soil conditioner and field water management,the integrated measures of soil conditioner and field water management technology have a greater decrease in the content of Cd in the organs of ordinary rice cultivars Yixiangyou 2115 and Chuanyou 6203.The measurements with 200 kg/mu of conditioner + comprehensive prevention made the content of Cd in Yixiangyou 2115 was 47% lower than that in the control group,and the content of Cd in Chuanyou 6203 was 46% lower than that in the control group.If Yixiangyou 2115 under conventional field management was used as the control,the Cd content of Chuanyou 6203 brown rice with low accumulation of Cd was 68% lower than that of the control under the combined control measures of 200 kg/mu conditioner + flooding in the whole growth period.Among all of the processing,only 200 kg/mu conditioner prevention and 200kg/mu mix conditioner + flooded the comprehensive prevention measures in the whole stages under the condition of low Cd accumulation of 6203 rice varieties for Cd content is lower than the national food safety standards limit.In the rice planting area of Chengdu plain where the Cd pollution degree is similar to that of the test site.The technology of soil conditioner + field water management + Cd low accumulation rice varieties should be integrated to carry out the prevention and control of Cd pollution in rice.