Study On The Characteristic Of Cadmium Uptake By Different Rice Cultivars And Amendments Under Cadmium Contaminated Paddy Soil

In order to explore the safe production of paddy rice in cadmium-contaminated farmland,mildly polluted farmland was used as the test object in this paper,and five kinds of rice varieties and three passivators were used as experimental materials.Cadmium stress test and amendments test in Shaoxing were conducted on the basis of Cd contaminated soil to provide scientific theory and practical skills for safety outputs in contaminated areas.The main test results are as follows:?1?The results showed that four rice varieties had the appearance of Cd low accumulation in rice grain.When the Cd concentration in rice grain in Yongyou 538,Chunyou 84,Jiahe 218 and Xiushui134 was above 0.2 mg·kg^-1,the corresponding soil Cd concentrations were higher than 1.41mg·kg^-1,1.41mg·kg^-1,0.91mg·kg^-11 and 0.22 mg·kg^-11 respectively.The linear regression equation probably used in fitting the relationship between the Cd content in rice grain and the total Cd concentration in paddy soils.Under rice safe production,the order of the threshold value of the Cd concentration in paddy soil compared by rice variety was Yongyou538>Chunyou84>Jiahe218>Xiushui134,while the order of the threshold value of the Cd concentration in paddy soil compared by soil type was clay degleyic paddy soil>tidal mud percolating paddy soil>tital mud redoximorphic paddy soil;?2?The accumulation of Cd in different varieties of rice was related to the ability of Cd uptake by roots and Cd uptake into shoots.The transfer coefficient of root/shoot,shoot/root Cd could characterize the accumulation of Cd in rice;?3?All three amendments increased soil p H,but the rice straw biochar was even greater;The order of decreasing soil available Cd from high to low was zeolite biofertilizer?17.5%-19.8%?,attapulgite?9.3%-17.0%?and rice straw biochar?5.1%-8.7%?;?4?The effect of amendments in high accumulation of rice varieties is better than that of low accumulation rice varieties.All three kinds of amendments inhibited the Cd accumulation in different organs of rice,especially for Jia 58.The Cd content of rice was reduced by 49%in the application of rice straw biochar.However,due to the high accumulation of Jia 58,the content of Cd exceeded 0.2mg·kg^-11 in four kinds of rice that have been treated.In this experiment,the amendments did not have an obvious desensitization effect in Yongyou 538,whose Cd content did not exceed 0.2mg·kg^-1because of its low accumulation,unless otherwise treated by rice straw biochar;?5?Through the analysis,it was found that the amendments had a restraining effect on the transport ability of different rice varieties compared with the conventional fertilization treatment,and that the effect of zeolite biofertilizer in reducing the transport coefficient of Jia 58 was more obvious.Under the same desensitization treatment,the transpiration coefficient of Yongyou 538 root/soil was higher than that Jia 58.