Effects Of Bio-char On Activity Of Cadmium In Soils And Accumulation Of The Metal In Rice,Rape

In order to define the value in Cd contaminated soil by Bio-char explicitly.This paper mainly used Bio-char as a soil conditioner,selected 2 types of Cd contaminated soil (single Cd contaminated soil and heavy Cd contaminated soil),through indoor experiment of soil and outdoor pot experiment of rice and rape,respectively,to discusses the effects of Bio-char on activity of Cd and accumulation of Cd in rice and rape.The main results are as follows:(1)Choosed the 2 types of Cd contaminated soils to develop indoor soil culture experiment, under flooding conditions, applying different quantity of bamboo bio-char,in the incubation time of 5 d,10 d,20 d,40d collect samples moderated and respectively,to study the changes of Cd form in soils.The results shows that the application of bamboo bio-char can improve the pH value and reduce the content of exchangeable Cd in soils.What's more,the relationship between exchangeable Cd content and pH value in soils was significantly negative correlation.Through the cultivation of 40d, the 2 types of Cd contaminated soils,as the cultivation time extended,the applying bio-char content increased,the content of exchangeable Cd in soils is lower, the Cd activity index is lower,the application of 4% bamboo bio-char is more effective than other treatments. The flooding conditions to reduce the content of exchangeable Cd and the Cd activity index in single Cd contaminated soil have certain effect.(2)Choosed the single Cd contaminated soil to develop outdoor pot experiment for rice, to study the impact of single-applied bio-char for two rice harvest per year (early rice and late rice) absorbing and accumulating Cd. The results shows that, the application of 4% bamboo bio-char is more effective than other treatment. The 2 varieties of early rice (Num. 32 Xiang Zaoxian, Zhu Liangyou 819) and the 2 varieties of late rice (Num.23 Xiang Wanxian, Yu Zhenxiang) on absorbing and accumulating Cd shows a similar regulation, it shows that the single-applied bio-char can restrain two rice harvest per year on absorbing and accumulating Cd effectively.(3)Choosed the heavy Cd contaminated soil to develop outdoor pot experiment for rape, to study the changes of Cd forms in the soil of rape root and the effects of rape absorbing and accumulating Cd by different bio-char treatments. The results shows that, to reduce the contents of Cd in each parts of maturity rape(Num.27 Xiangyou) and the effectiveness of Cd in soil, the application of 1% caragana bio-char is more effective than other treatments.(4)Choosed the heavy Cd contaminated soil to develop outdoor pot experiment for rice, to study the effects of combine bamboo bio-char and spraying with silicon fertilizer on rice absorbing and accumulating Cd. The results shows that, to restrain the two varieties of rice (Zhu Liangyou 819,Yu Zhenxiang) on absorbing and accumulating Cd, the combined action by the application of 0.5% bamboo bio-char and spraying with silicon fertilizer is more effective than other treatments.