Silicon enhancement of nitrogen use efficiency in plants: insights from soil nitrogen transformation, plant nitrogen uptake, assimilation, and remobilization

Severe nitrogen (N) deficiency inhibits crop growth and yield, while low use efficiency of N fertilizer causes resource waste and environmental harm. Enhancing crop N use efficiency (NUE) is thus a critical scientific challenge. Ecofriendly and cost-effective silicon (Si) fertilizer can enhance NUE across the entire soil-plant continuum. Si-mediated improvements in soil physicochemical properties and microbial community structure underlie enhanced mineralization and suppressed denitrification. Si–cell wall interactions support symbiont recognition, nodule initiation, and formation of functional nodules for sustained N 2 fixation. Si also upregulates genes encoding N transporters and assimilatory enzymes to improve N uptake, assimilation, and remobilization. This mini-review synthesizes Si’s roles in regulating soil N transformation and plant N uptake, assimilation, and remobilization. It aims to support precision Si fertilization strategies that reduce synthetic N input without compromising yield.