Effects of different organic fertilizers on soil properties and vegetable quality in acidic red soil dryland

To study the effects of different organic fertilizers on the chemical properties of acidic red soil and yield and quality of vegetables, a field experiment was conducted with five treatments: no fertilizer (NF), chemical fertilizer only (NPK), pig manure organic fertilizer (PM), cattle manure organic fertilizer (CM), and bio-organic fertilizer (BM). Soil chemical properties, carbon cycle-related enzyme activities, and vegetable yield and quality indicators were analyzed. The results show that compared with the NPK treatment, the application of organic fertilizers significantly increases soil pH (P<0.05), improves soil acidity indicators, and increases total organic carbon and easily oxidized organic carbon content in the soil . Among them, the total organic carbon in CM and BM increases by 48.6% and 45.2%, respectively (P<0.05); and total nitrogen, available potassium, available phosphorus, alkali-hydrolyzable nitrogen and cation exchange capacity are also improved to varying degrees. The BM treatment exhibits the most significant effect on improving soil chemical properties. The application of organic fertilizers increases all soil carbon cycle-related enzyme activities significantly except for β-glucosidase, with the CM treatment being the most effective. Compared with the NPK treatment, the amylase and sucrase activities in the CM treatment increase by 2.78 and 7.15 times, respectively (P<0.05). The application of organic fertilizers significantly increases vegetable yield overall, but has no significant effects on Vc, total acid and soluble sugar content. No significant differences in vegetable yield and quality among different organic fertilizer treatments are found. The application of organic fertilizers can inhibit the increase in soil total acid caused by the application of chemical fertilizers alone, increases carbon content and related enzyme activities, thereby increasing vegetable yield and quality. Cattle manure organic fertilizer and bio-organic fertilizer are more effective than pig manure organic fertilizer in improving the acidic red soil in dryland.