水稻秸秆草木灰对镉污染水稻土修复效果研究

Study on the Remediation Effects of Rice Straw Ash on Cadmium Contaminated Paddy Soil

摘要: 为探讨水稻秸秆草木灰对镉(Cd)污染水稻土的修复效果，在低、高两种镉含量水稻土中分别添加不同量(低H1、中H2、高H3)水稻秸秆制成的草木灰，通过盆栽试验，研究添加草木灰后土壤中有效态Cd含量及稻米中Cd含量的变化。结果表明：添加草木灰后，两种Cd含量水稻土pH值与对照相比无显著差异(P > 0.05)。添加草木灰使两种镉含量水稻土有效态Cd含量降低，相比对照降幅在27.5%~49.6%之间；相同草木灰添加量，高Cd含量水稻土土壤有效态Cd含量降幅较大，低Cd含量水稻土次之。低Cd含量水稻土中添加草木灰后，稻米Cd含量降低，且添加量为H3时降幅最大；高Cd含量水稻土添加草木灰后，稻米Cd含量与对照相比无显著差异(P > 0.05)。研究表明：草木灰降低稻米Cd含量的效果受到土壤本身Cd含量的影响，在一定土壤Cd含量范围内施用合适的量才能保证其修复效果。

Abstract: In order to better understand the remediation effects of rice straw ash on cadmium (Cd) contami-nated paddy soil, a pot culture experiment was conducted to study the effects of applying different amounts of rice straw ash (low dosage: H1, medium dosage: H2, high dosage) to paddy soil on Cd availability in paddy soil and Cd content in rice. The results showed that, there was no significant difference in pH values between the two types of soils with different Cd contents and the control soils (P > 0.05). The available Cd content in two different Cd content paddy soils decreased by 27.5%~49.6% due to adding rice straw ash. As the same dosage of rice straw ash was added, the decrease ranges of available Cd content in paddy soils were ordered from high to low as follows: paddy soil with high Cd content  paddy soil with low Cd content. Due to the addition of rice straw ash, Cd content in rice decreased in paddy soil with low Cd content, but there was no significant difference in Cd content in rice between paddy soils with high Cd content and the control soils (P > 0.05). The results indicated that the effect of rice straw ash on Cd content in rice was affected by the Cd content of the soil itself, and only when the Cd content in soil is within a certain range and an appropriate amount of ash is applied, the repair effect of Cd pollution can be guaranteed.