| Chengdu Plain is one of the major grain-producing areas in Sichuan Province.Long-term industrial and mining activities and unreasonable fertilization and drug use habits make the soil pollution of cultivated land in this area increasingly serious,especially Cd pollution.Farmland soil Cd pollution is a serious threat to food security problems.It have been found that our country farmland soil Cd pollution is increasingly serious.Therefore,it is of great significance to carry out feasible treatment of soil heavy metal Cd pollution and reduce the content of Cd in grain to ensure food security and people’s health.Wheat is one of the world’s most important food crops,providing food for more than one-third of the world’s population.Cadmium severely restricts the safe production of wheat due to its high toxicity,high mobility and wide pollution area.The genetic factors and cadmium accumulation ability of wheat with different genotypes were different,which provided conditions and basis for the screening of wheat materials with low cadmium accumulation.Therefore,in this study,11 wheat varieties were screened for cadmium accumulation ability.Combined with the foundation of previous studies,soil conditioner passivation effect test was carried out to explore the wheat Cd pollution control model applicable to the Chengdu plain.The main results are as follows:（1）In the field screening test,the yield of 11 wheat varieties was between 241-349 kg/mu,and the Cd content in their grains was between 0.080-0.160 mg kg-1.Among the 11wheat varieties,the variety with higher yield and lower Cd content was Chuannong 30.The cultivar with relatively high yield and low Cd content was Mianmai 228.Therefore,low-accumulation cadmium material Chuannong 30 and ordinary material Mianmai 228were obtained by screening.The Cd content of Chuannong 30 grain was 0.091 mg kg-1and the yield was 339 kg/mu;The Cd content of Mianmai 228 grain was 0.160 mg kg-1and the yield was 283 kg/mu.（2）Biochar,bacterial residue,modified sepiolite and mixed conditioner could effectively reduce Cd content and Cd accumulation in wheat.Compared with single conditioner raw material,the same amount of mixed conditioner has better ability of prevention and control of soil Cd contamination when the dosage of mixed conditioners is200 kg/mu,mixed conditioners can reduce common varieties of cotton wheat Mianmai 228grain Cd content of 34.7%,can drop to Chuanmai 30 Cd accumulation of low efficiency,Cd content of 37.5%,Cd pollution of heavy metals in wheat under the condition of the best effect.Therefore,200 kg/mu mixed conditioner has the best effect on Cd pollution control in Chengdu plain wheat area.In addition,by analyzing the root stem transfer coefficient and stem grain transfer coefficient of Cd under various conditions,it is found that the root stem transfer coefficient of Cd is between 0.354-0.461,and the difference is relatively small under various conditions.The stem grain transfer coefficient of Cd ranged from0.179 to 0.323.The stem grain transfer coefficient of Cd in Chuannong 30 was significantly lower than that of Mianmai 228,and the stem grain transfer coefficient of Cd decreased gradually with the increase of the amount of mixed conditioner..（3）Cd pollution control technology with Cd reduction effect well and economic benefits is the general direction of Cd pollution control of cultivated land.The research and development of economic and applicable Cd pollution control technical measures is of great practical significance to reduce the Cd content of grain crops and improve the level of food security.This research analyzed the remediation effect of the soil conditioner and its raw materials developed by our research group on the cultivated land in the Chengdu plain wheat area polluted by Cd.It was found that the soil conditioner had a significant remediation effect on the Cd pollution in the Chengdu plain wheat area,and the Cd content of wheat grain could be reduced by about 35%at the dosage of 200 kg/mu. |
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