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.
Keywords: Economic Benefit; Fertilization Strategy; Forage Yield; Rice Straw; Silage Fermentation.