A New Soil Conditioner Study On The Effect Of Reducing Cadmium In Tobacco And Rice

Hunan province is one of the areas which farmland soils were polluted relatively severe by Cd in China, and both the tobacco and rice are the main cash and grain crops in Hunan province. The effects of a new type of soil conditioner —"Kedaolibuliao" on the growth, the distribution of Cd absorption, and the main mineral nutrition elements of tobacco and rice under cadmium stresses were studied to provide repair material for repairing Cd polluted farmland soils through pot and cultivating experiment. The main results as follows:(1)The experiment of soil conditioner different using level showed that the suitable application levels of soil conditioner was 0.4g/kg because it could significantly reduce the Cd contents in tobacco and be beneficial to the growth and the main mineral nutrient elements absorption of rice.(2)Based on the tested soil without exogenous available Cd although there were no promotion in the growth of tobacco and rice to use 0.4g/kg soil conditioner, the Cd contents of tobacco leaves and brown rice could reduce. The content of Cd in the upper leaves and middle-lower leaves fell by 23.4% and 7.8% respectively, the Cd content in rice reduced by 70.7%.(3) After adding exogenous Cd into the tested soil, the soil conditioner could promote the growth of of tobacco under cadmium stresses, and reduce the content of Cd in tobacco leaves. When applying soil conditioner (0.4g/kg) on soils which the exogenous available Cd concentration were 0.6mg/kg and 1.2mg/kg, the decreasing percent of tobacco middle-lower leaves were 15.1% and 43.3% respectively. The distribution of Cd in tobacco as follows:the middle -lower basic leaves was bigger than top leaves and stalks.(4) Soil conditioner could improve the absorption of P?Zn?Cu?Cd and meanwhile could reduce the absorption of Ca?Mg?K under cadmium stresses (1.0-5.0mg/kg Cd). The Cd content in root system was biggest followed by the stalk and the Brown rice was the least.(5) Flooding simulation training test showed that soil conditioner reduced the content of available Cd in soil, which reduction was 22.8%. Reducing the soil available Cd was the main reason for reducing the absorption of tobacco.