Selenium (Se) is an essential trace element in the human body. Se-enriched agricultural products, obtained by applying Se fertilizer, are important sources of Se supplement. However, Se fertilizer may cause a series of environmental problems. This study investigated the transformation of exogenous selenium nanoparticles (SeNPs) and selenite (SeO₃^2–) in soil and explored their effects on soil microbial community and typical microorganisms. SeNPs exhibited a slow-release effect in soil, which promoted the growth of soil microorganisms and enriched soil probiotics. SeO₃^2– was converted to a stable and low toxic state in soil, increasing persistent free radicals and decreasing microbial abundance and diversity. The influences of SeNPs and SeO₃^2– on two typical soil microorganisms (Bacillus sp. and Escherichia coli) were also evaluated, and SeNPs were more difficult to enter into microorganisms directly, with lower toxicity and higher safety. These results indicated that SeNPs were a more environment-friendly Se additive for agriculture applications. This work provides useful information for better understanding the environmental fate and behavior of Se fertilizer in the soil.

硒（Se）是人体必需的微量元素。施硒肥获得的富硒农产品是补充硒的重要来源。然而，硒肥可能会造成一系列环境问题。本研究调查了外源硒纳米颗粒（SeNPs）和亚硒酸盐（SeO ₃ ^2-）在土壤中的转化，并探讨了它们对土壤微生物群落和典型微生物的影响。SeNPs在土壤中表现出缓释作用，促进了土壤微生物的生长，丰富了土壤益生菌。SeO ₃ ^2-在土壤中转化为稳定且低毒的状态，增加持久性自由基并降低微生物丰度和多样性。SeNPs和SeO ₃的影响^2–两种典型的土壤微生物（芽孢杆菌sp. 和大肠杆菌)，SeNPs更难直接进入微生物，毒性更低，安全性更高。这些结果表明，SeNPs 是一种更环保的农业应用硒添加剂。这项工作为更好地了解土壤中硒肥的环境归宿和行为提供了有用的信息。