有机物料对农田土壤肥力及镉有效性的影响

明确有机物料对土壤肥力及Cd有效性的影响，对南方中轻度Cd污染农田的安全利用具有重要意义。本研究以我国南方两种不同程度Cd污染农田土壤为研究对象，通过不同有机物料（猪粪、商品有机肥、水稻秸秆和生物炭）施肥处理来探究土壤肥力水平及Cd有效性的变化，并对施用有机物料情况下土壤Cd有效性与土壤养分进行了关联分析。结果表明，施用有机物料显著提高了土壤氮磷钾含量及其有效性，商品有机肥提高了土壤全N含量，施用猪粪处理土壤的全P和有效P含量显著升高，商品有机肥和生物炭明显提高了土壤全K和速效K含量。水稻秸秆和生物炭处理轻污染土壤SOM均达土壤肥力1级（> 40 g/kg）。与CK相比，施加有机物料对轻污染土壤有效态Cd含量的影响不大，但中污染土壤有效态Cd含量显著下降，最高降幅达20.00%。土壤有效态Cd含量与全N、全P和全K和有效P均成显著负相关关系。轻污染土壤施加猪粪和生物炭处理上海青地上部Cd含量均低于0.20 mg/kg。施加商品有机肥处理两种土壤肥力综合指数（SNI）最高，是其他处理的1.50~3.18倍，但其上海青地上部Cd含量存在较高风险。因此，针对南方Cd污染农田土壤的培肥及安全利用可考虑施用猪粪。

Effects of organic material on soil fertility and cadmium availability in farmland

It is important to understand the effects of organic material on soil fertility and Cd availability for the safe utilization of Cd contaminated farmland in southern China. In this study, two different degrees of Cd contaminated farmland soil in southern China were used to study the changes of soil fertility and Cd availability during crop growth by applying different organic manure (pig manure, commercial organic manure, rice straw and biochar), and the correlation analysis between soil Cd availability and soil nutrients was analyzed. The results showed that application of organic material significantly increased content and availability of N, P and K in soil, the application of commercial organic manure increased the content of total N in soil, the application of pig manure treatment significantly increased the content of total P and available P, and the application of commercial organic manure and rice straw biochar significantly increased the content of total K and available K in soil. The soil organic matter (SOM) contents of the lightly contaminated soil treated with rice straw and biochar increased to level 1 (> 40 g/kg). Compared with CK, the effect of organic material on the content of available Cd in lightly contaminated soil was not significant, but the content of available Cd in moderately contaminated soil decreased significantly, with a maximum reduction of 20.00%. The content of available Cd was negatively correlated with the content of total N, total P, total K and available P. The Cd content in the aboveground of Brassica chinensis. L treated with pig manure and biochar was lower than 0.20 mg/kg. The soil nutrient index (SNI) of the two different degrees of Cd contaminated farmland soil with the treatment of commercial organic manure was the highest, which was 1.50~3.18 times that of other treatments, but the Cd content in the aboveground of Brassica chinensis. L. had a higher risk. Therefore, the application of pig manure can be considered for the cultivation and safe utilization of Cd contaminated farmland soil in southern China.