In acidic Cd-contaminated soils, soil nitrogen conversion is inhibited and usually block nitrogen supply for plants. Earthworms are well known for improving soil properties and regulating various soil biogeochemical processes including nitrogen cycling. To figure out the effect and mechanisms of earthworms on soil nitrogen transformation in Cd-contaminated soil, ten treatments with and without A. robustus in five soil Cd concentration gradients were established. The tolerant concentration of A. robustus to Cd in the acidic soil is about 6 mg kg^-1. The potential ammonia oxidation of the acidic soils was very low, ranging from 0.05 to 0.1 µg NO₂^--N g^-1 d^-1. Although AOA was more abundant in the acidic soil than AOB, AOA was inhibited by Cd pollution, while AOB showed some increase under Cd-stress. AOA may play a dominant role in ammonia oxidation in acidic soil, but the recovery of nitrification in Cd-contaminated acidic soil was probably due to the effect of AOB. Earthworms significantly increased soil pH, DOC, ammonium and PAO, thus promoted soil ammonification and potential nitrification, but had no significant effect on soil net nitrification. Correlation analysis results demonstrate that earthworms may promote soil PAO by increasing soil pH, NH₄⁺-N content, and AOB abundance. This study could provide a theoretical basis for solving the problem of nitrogen-cycling-functional degradation and nitrogen supply in the process of phytoremediation of heavy metals-contaminated soils.

在酸性镉污染的土壤中，土壤氮的转化受到抑制，通常会阻碍植物的氮供应。improving因改善土壤特性并调节各种土壤生物地球化学过程（包括氮循环）而闻名。为了弄清worm对Cd污染土壤中氮素转化的影响及其机理，建立了在五个土壤Cd浓度梯度下有或没有强壮曲霉的十种处理方法。酸性土壤中强壮曲霉对Cd的耐受浓度约为6 mg kg ^-1。酸性土壤的潜在氨氧化非常低，范围为0.05至0.1 µg NO ₂ ^-- N g ^-1 d ^-1。尽管酸性土壤中AOA比AOB丰富，但AOA受到Cd污染的抑制，而AOB在镉胁迫下表现出一定的增加。AOA可能在酸性土壤的氨氧化中起主要作用，但是Cd污染的酸性土壤中硝化的恢复可能是由于AOB的作用。significantly显着提高了土壤的pH，DOC，铵和PAO，从而促进了土壤的氨化作用和潜在的硝化作用，但对土壤净硝化作用没有显着影响。相关分析结果表明，may可能通过增加土壤pH，NH ₄ ⁺促进土壤PAO。-N含量和AOB含量。该研究可为解决重金属污染土壤的植物修复过程中氮循环功能退化和氮供应问题提供理论依据。