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 α-diversity of bacteria and significantly altered the β-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.