In order to promote the recycling of vegetable waste into fields, different amounts of tomato straw and cabbage leaf residues(full amount: 1.8 t per 667 m2, half amount: 0.9 t per 667 m2)were simulated in the laboratory. Treatments comprising addition of different inoculants(composting agents, agricultural enzymes)and no added decomposing agents were applied. Soil temperature, pH, electrical conductivity, organic carbon, nutrient content and humus composition content were recorded 7, 14, 21, 28, and 35 d after waste was returned to the field to explore the effects of different volumes of vegetable waste returned and decomposing agent on soil physical-chemical properties and humus composition. The results show that the pH value of soil under waste return treatments first decreased and then increased. The pH value of the treatment with microbial agents changed only slightly. The organic carbon content of each treatment increased rapidly 7 days after the vegetable waste was returned to the field; the increase ranged from 0.55 g·kg-1 to 1.73 g·kg-1. Compared with returning waste to the field without using fungicides, the total nitrogen, alkali-hydrolyzable nitrogen and available potassium content in the soil following full tomato straw return with enzyme application increased by 14.49%, 9.30% and 5.61%, respectively. The increase in available phosphorus content with the full amount of returned cabbage leaf residues and combined application of enzymes was the largest, reaching 34.98%, 35 days after returning. During the returning treatment, the water -soluble substance content of tomato straw reached its maximum on day 21, while that of cabbage leaf residue increased to its maximum on day 7. The water -soluble substance content of the cabbage leaf residue returning treatment was higher than that of tomato straw. Returning the full amount of vegetable waste in conjunction with enzyme application can effectively promote an increase in soil humus and humic acid content. The soil humus degree of the two vegetable waste returning treatments reached a maximum 7 d after returning. Following a comprehensive comparison, it can be concluded that the full return(1.8 t per 667 m2)of vegetable wastes combined with enzymes has the best effect on improving straw resource utilization efficiency and reducing returning cost, which makes it most suitable for popularization and application. |