| The rice Cd accumulation and soil Cd availability is closely related to find out the influence factor of Hunan paddy soil Cd availability of rice and the accumulation of Cd,this study used pot experiment was discussed on the following three aspects:(1)the two consecutive quarter of rice planting,regulating soil pH effects on soil Cd morphology,effectiveness and the accumulation of Cd;(2)to compare the differences between different varieties in different parts of rice in different growth period,the accumulation of Cd,the effects of different rice varieties to rice Cd accumulation.(3)the effects of soil total Cd and soil organic matter on Cd availability and Cd accumulation in rice were studied with the paddy soils with different pollution levels as the research object.The main research results are as follows:(1)Under the experimental conditions,improve the soil pH value can effectively reduce the available Cd content in soil,compared with the soil pH value was 4,5,6,the content of pH was 7 and 8 when the content of the available Cd decreased37.0%-77.5%;test conditions;soil pH rising up significantly decreased the Cd uptake of rice.To improve the grain yield of rice,in the soil pH value was 6,three kinds of rice grain weight were highest and different Cd content is low;the same soil under the condition of pH,there was no significant difference between the content of available soil Cd the second quarter with the first quarter,were decreased with the increase of soil pH and Cd contents in different parts of the second season of rice is still lower with the increase of soil pH value and.Therefore,to reduce Cd as one of the important goals of the red soil paddy soil pH adjustment,the adjustment of the reference value recommended for pH 6,soil pH was stable,the second quarter effectof small amount of conditioner on soil Cd availability and rice Cd accumulation had no significant difference with the first quarter.(2)Under the same experimental conditions,rice varieties in different parts and the content of Cd in each growth period significantly,soil pH 5,harvest Milyang12085 root Cd content was 6.11 mg kg-1,under the same conditions Guodao 6 root Cd content was 1.70 mg kg-1,the maximum value and minimum value is reached more than 3 times,the differences among varieties reached significant level(P < 0.05);rice rice plants Cd Cd concentration and total accumulation are related,and rice root Cd accumulation has a significant positive correlation between rice and shoot Cd accumulation showed no significant correlation;rice in heading-accumulation the harvest period for Cd percentage of total students long-term accumulation of the highest,followed by sowing tillering stage,tillering and heading for the small proportion.(3)3 different degree of pollution in red soil Cd in acid extractable state are mainly residual secondary,reducible and oxidizable concentration of total Cd ratio is very low and the difference was not significant(P > 0.05),the soil pH and Cd acid extractable state concentration was negatively correlated,and the content of organic matter were Cd content and four kinds of significant correlation;3 kinds of leaching agent to extract soil available Cd content by correlation analysis showed that 0.01 mol L-1CaCl2 extraction and the effective content of rice between the Cd content of the strongest;in 3 different Cd pollution degree of soil on the results the pot experiment showed that the high pollution soil treatment Cd content in different parts of rice were higher than the same period in light pollution and soil pollution,soil pollution and high Cd content in rice and pollution and light pollution treatment Cd content of rice was significantly different(P < 0.05),while the content of Cd in contaminated paddy soil treated with Cd was not significant(P > 0.05). |
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