Optimized Controlled-Release Fertilization Improves Productivity and Reshapes the Rhizosphere Microbiome in Lei Bamboo: A Metagenomic Assessment.

Intensive nitrogen fertilization in Lei bamboo (Phyllostachys praecox) plantations has increased productivity but has also reduced nitrogen-use efficiency (NUE), accelerated nutrient losses, and contributed to soil degradation. How nutrient-release strategies influence rhizosphere microbiome assembly and ecosystem functioning remains poorly understood. Here, we developed a bamboo shoot-specific controlled-release fertilizer (CRF) and evaluated different urea-CRF blending ratios to identify sustainable fertilization strategy for Lei bamboo production. Mixed CRF-urea treatments outperformed both sole-fertilizer applications and the unfertilized control. T2 (30% urea + 70% CRF) achieved the highest shoot yield, whereas T3 (50% urea + 50% CRF) enhanced NUE. Optimized fertilization improved soil nutrient availability and organic matter accumulation without significantly affecting soil pH. Metagenomic analysis revealed the enrichment of taxa associated with nutrient transformation, organic matter turnover, and plant growth. However, pathway-level analysis revealed shifts in carbon, nitrogen, and sulfur cycling activities under optimized nutrient-release regimes. Our results demonstrate that synchronizing nitrogen release with plant and microbial demand enhances rhizosphere function, productivity and NUE. T2 delivered the strongest overall agronomic performance by maximizing shoot yield while maintaining improved nutrient retention and ecological stability. These findings provide a mechanistic link between fertilization strategy, rhizosphere microbial dynamics, and ecosystem function, supporting sustainable Lei bamboo production.