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 N2 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.