Enhancing maize yield stability, soil health, and microbial diversity via long-term manure practices: Insights from a 14-year trial

Identifying efficient nutrient management strategies is crucial for maintaining soil health and boosting crop production. A 14-year field experiment with no nitrogen fertilizer (CK), urea with 200 kg N ha-1 (U200), urea with 100 kg N ha-1 (U100), manure with 200 kg N ha-1 (M200), manure with 100 kg N ha-1 (M100), and urea with 100 kg N ha-1 plus manure with 100 kg N ha-1 (U100M100) was conducted to assess the effects on soil quality, microbial diversity and yield sustainability. Long-term fertilization increased the alpha-diversity of bacteria and significantly altered the beta-diversity of both bacteria and fungi. Prolonged fertilization significantly augmented soil nitrogen and phosphorus levels. Concomitantly, the activities of urease, invertase, and alkaline phosphatase were substantially elevated. Compared with U200, M200 and U100M100 raised the soil quality index (SQI) by 27-35 % and 11-24 %, respectively. Long-term manure application increased yield by 42-51 % compared with CK. Furthermore, manure application promoted yield stability (CV) and sustainable yield index (SYI) from 2017 to 2023. Notably, U100M100 improved yield, SYI, and SQI more effectively. SQI significantly correlated with yield, SYI, and CV, suggesting its importance for sustainable production. A partial least squares path model showed that the bacterial community influenced SQI by modulating soil nutrients, and the fungal community impacted SQI by affecting soil enzyme activities. Ultimately, these microbial-mediated effects on SQI influenced crop yield. Overall, substitution of partial mineral fertilizers with manure is a promising strategy for sustainable agricultural production in terms of improving soil health and yield sustainability.