Improving soil quality and crop yield of fluvo-aquic soils through long-term organic-inorganic fertilizer combination: Promoting microbial community optimization and nutrient utilization

Abstract

Organic-inorganic fertilizer combination is crucial for reducing dependence on mineral fertilizers and enhancing the efficient utilization of agricultural waste resources. However, research on the long-term impacts of substituting chemical fertilizers with straw and organic fertilizers on soil quality and microbial community structure in fluvo-aquic soils, particularly the relationship between functional microbial communities and soil quality, remains limited. This study aimed to clarify the impact of long-term application of straw and organic fertilizers as substitutes for 30 % of chemical fertilizers on soil quality, crop yield, and functional microbial communities from a 33-year history national fluvo-aquic soil observation station. The results indicated that the substitution of straw and organic fertilizers significantly promoted the abundance of functional bacterial communities (such as Sphingomonas and MND1 ) and fungal communities (such as Mortierella ) that are positively correlated with soil quality and crop yield. This, in turn, improved soil quality (by 12.6–56.9 %), and N and P fertilizer use efficiency (NUE: 4.11–11.8 %; PUE: 3.32–22.6 %), and crop yields (4.21–12.7 %). Furthermore, the substitution of chemical fertilizers with organic fertilizers yielded more pronounced effects than straw substitution. Structural equation modeling and principal component analysis identified that soil quality and functional microbial communities as critical drivers of increased crop yield. Notably, soil quality exerted a significantly stronger impact on bacterial communities than on fungal communities. These findings enrich our understanding of the relationship between soil quality and functional microbial communities, providing valuable insights for optimizing nutrient management and advancing sustainable agricultural practices, particularly in fluvo-aquic soil regions. • Organic-inorganic fertilizer combination improved soil quality and crop yield. • Organic fertilizers had a more pronounced effect than straw. • Organic amendments boosted specific microbial communities and nutrient efficiency. • Soil quality and microbial communities are key drivers of increased crop yield. • Soil quality influenced bacterial communities more than fungal communities.