Abstract

Nano-fertilizers, engineered nanomaterials designed to enhance nutrient delivery, are increasingly used in agriculture to improve crop productivity. This study investigates their impact on soil microbial functions, including microbial biomass, enzyme activities, and community composition, in temperate and semi-arid agricultural soils. Field and laboratory experiments assessed the effects of nano-nitrogen (nano-N) and nano-phosphorus (nano-P) fertilizers compared to conventional fertilizers. Nano-fertilizers increased microbial biomass carbon (MBC) by 10–20% and enzyme activities (e.g., β-glucosidase, phosphatase) by 15–25% in temperate soils but showed variable effects in semi-arid soils. Microbial community shifts favored nitrogen-fixing bacteria under nano-N application. While nano-fertilizers enhanced nutrient availability, potential risks include microbial stress at high doses. These findings suggest that nano-fertilizers can support soil health but require careful management to avoid adverse microbial impacts.