Abstract: As one of the important reservoirs of selenium (Se), soil is an important material basis for Se to enter the food chain through plants. The content of soil Se is therefore the key factor affecting the Se level of edible crops. Rainfall plays an important role in driving soil Se input and output. Elucidating the influence of rainfall on soil Se is essential to better understand the spatial distribution of soil Se at a national scale. Based on analysis of the latest researches in China and abroad, we found that rainfall is an important route for soil Se input, by comparing the Se input from wet deposition between the Se-rich area of Southeast China and the low-Se belt stretching from Northeast China to Southwest China. The role of rainfall in the formation of low-Se belt and endemic diseases was revealed by summarizing the impacts of rainfall on soil Se leaching loss and its bioavailability. Finally, we discussed the natural and artificial factors that influence the effects of rainfall on soil Se, such as climate, soil, plant and human activities. To better forecast the variation trend of soil Se in the future, it is necessary to synthetically study the multiple processes that govern soil Se migrations.

Key words: Loess Plateau, temperate forest., diversity, soil microbial community composition