New insight into the effects of integrated organic-inorganic fertilization on enhancing the rice straw productivity and silage quality

Abstract

Objective The objective of this study was to determine the overall benefits of organic-inorganic integrated fertilization for the rice straw production system, including yield, forage nutritive value, silage fermentation quality, and economic returns. Methods The field experiment used a completely randomized design with six treatments, defined by the proportion of organic manure (OM) nitrogen substituting chemical fertilizer (CF) nitrogen: T0 (0%, unfertilized control), T1 (0% OM, 100% CF), T2 (25% OM, 75% CF), T3 (50% OM, 50% CF), T4 (75% OM, 25% CF), and T5 (100% OM, 0% CF), to assess their impacts on rice straw yield, forage quality, and silage fermentation. Results The results from the 2023–2024 trials demonstrated that T2 performed optimally. Compared to T1, T2 showed more tiller numbers (12 vs. 9 per plant), and greater yields of fresh straw (18,033.43–19,483.17 vs. 15,474.17–15,739.34 g/kg), dry matter (DM) (5,610.20–6,061.11 vs. 5,361.80–5,454.20 g/kg), and grain (7,419.42–7,531.34 vs. 7,703.96–7,841.05 g/kg DM). Nutritionally, T2 improved straw quality by elevating crude protein and water-soluble carbohydrate content while reducing fiber components. After 60 days of ensiling, treatment T2 achieved successful and desirable fermentation quality, as evidenced by a sufficiently low pH value (~3.84), a high population of lactic acid bacteria (5.6 log10 cfu·g−1 FM), moderate lactic acid production (~3.19 g/kg DM), and minimal protein degradation reflected by an acceptably low ammonia nitrogen concentration (~2.41 g/kg total nitrogen). Economically, T2 also achieved the highest net benefit (2,568 USD·ha−1). Conclusion The 75% chemical plus 25% organic fertilizer regime represents a viable strategy for achieving agricultural sustainability, as it effectively supports high grain production while also improving straw yield, quality, and silage fermentation, resulting in higher economic returns.