Improvement of Yield and Quality Properties of Radish by the Organic Fertilizer Application Combined with the Reduction of Chemical Fertilizer

Chemical fertilizers can improve crop productivity, but irrational fertilization often results in low crop quality and yield, poor soil fertility, and severe environmental pollution. Nevertheless, little research has been conducted with a close focus on the cultivation of radish in high mountain regions, a widely cultivated root vegetable known for its nutritional value and economic importance. Here, a method of reducing chemical fertilizers combined with the application of organic fertilizers is proposed upon studying four different ratios of chemical and organic fertilizers, including control (375 kg·ha−1 chemical fertilizer + 4500 kg·ha−1 organic fertilizer) and combinations (T1: 12% reduction in chemical fertilizer + 4500 kg·ha−1 organic fertilizer; T2: 20% reduction in chemical fertilizer + 4500 kg·ha−1 organic fertilizer; T3: 28% reduction in chemical fertilizer + 4500 kg·ha−1 organic fertilizer). Their effects on radish quality, yield, and soil environment were investigated. Compared with the control group, T2 significantly increased radish yield by 12.92% and improved the contents of vitamin C, soluble sugars, sulforaphane soluble solids, and titratable acidity in the radish roots by 10.62%, 2.15%, 50.00%, 26.90%, and 43.90%, respectively. The soil nutrient content was increased by the T2 treatment, with a 7.69% and 14.29% increase in total nitrogen and total phosphorus content, respectively, compared with the control. Moreover, soil urease activity, sucrase activity, alkaline phosphatase activity, and catalase activity were significantly enhanced by the T2 treatment, showing an improvement of 11.13%, 44.30%, 26.41%, and 9.33% compared with the control, respectively (p < 0.05). The relative abundance of beneficial bacterial phyla such as Proteobacteria and Actinobacteria was increased in the T2 treatment, potentially helping to maintain better soil health and long-term fertility. In summary, a promising fertilizer management strategy is herein unveiled through the reduction of chemical fertilizers and the application of organic fertilizer that not only improves radish yield and quality but also optimizes the soil environment, providing an effective means for sustainable crop production.