不同肥料长期施用下稻田镉、铅、铜、锌元素总量及有效态的变化

以中国科学院桃源农业生态实验站的长期田间定位试验为基础,研究了16年长期定量施肥对土壤Cd、Pb、Cu和Zn积累及其有效性的影响。结果表明:单施化肥可使土壤Cd含量降低、Pb含量增加,对Cu和Zn的积累无显著影响,水稻收获时的移出效应可能是Cd含量降低的主要原因;与单施化肥相比,有机物料循环可提高土壤Cd和Pb的积累,但对Cu和Zn的积累无显著影响。试验期内单施化肥对土壤Cd、Pb、Cu和Zn的有效性无显著影响;有机物料循环可显著提高Cd和Zn的有效性,这与有机物料循环引起的土壤有机质含量增加和pH降低有关。

Variations of total and available Cd, Pb, Cu and Zn in red paddy soils under long-term fertilization

Based on the long-term experiment in Taoyuan Agroecosystem Experimental Station of Chinese Academy of Sciences, this paper studied effects of long-term quantitative fertilization on accumulation and availability of Cd, Pb, Cu and Zn in the red paddy ecosystem. The application of chemical fertilizers decreased the concentration of Cd in soil, and Cd uptake by rice might be the main reason for this. When recycling of organic matter brought some nutrient elements back into the soil, Cd was among them. The effect of the recycling changing soil properties and hence soil Cd played a more important role than the effect of Cd uptake by rice in accumulation of Cd in the soil. Both application of chemical fertilizers and recycling of organic matter increased Pb in the red paddy soil, but did not have any significant effect on Cu and Zn. Long-term application of chemical fertilizers had little effect on Cd, Pb, Cu and Zn, while recycling of organic matter improved availabilities of Cd and Zn significantly. The increase in soil organic matter and the decrease in soil pH caused by recycling of organic matter might be the main reason for the promotion of availabilities of Cd and Zn.