Although the global nitrogen (N) cycle is largely driven by soil microbes, plant root exudates can profoundly modify soil microbial communities and influence their N transformations. A detailed understanding is now beginning to emerge regarding the control that root exudates exert over two major soil N processes – nitrification and N₂ fixation. We discuss recent breakthroughs in this area, including the identification of root exudates as nitrification inhibitors and as signaling compounds facilitating N-acquisition symbioses. We indicate gaps in current knowledge, including questions of how root exudates affect newly discovered microbial players and N-cycle components. A better understanding of these processes is urgent given the widespread inefficiencies in agricultural N use and their links to N pollution and climate change.

尽管全球氮（N）循环很大程度上是由土壤微生物驱动的，但植物根系分泌物可以深刻改变土壤微生物群落并影响其氮转化。_{关于根系分泌物对两个主要土壤氮过程——硝化作用和N 2}固定——的控制作用，现在已经开始有了详细的了解。我们讨论了该领域的最新突破，包括鉴定根系分泌物作为硝化抑制剂和促进氮获取共生的信号化合物。我们指出了当前知识的差距，包括根系分泌物如何影响新发现的微生物参与者和 N 循环成分的问题。鉴于农业氮利用普遍效率低下及其与氮污染和气候变化的联系，迫切需要更好地了解这些过程。