Effects of different winter planting patterns on carbon management index of paddy field

The middle and lower reaches of the Yangtze River region is an important base for rice production in China, which plays an important role in ensuring China's food security. However, the utilization rate of paddy field resources in winter was not high in this area. In this study, the effects of different winter planting patterns on soil quality were discussed, which would contribute to the rational development and utilization of winter fallow fields and provide theoretical basis for improving the sustainability of paddy fields. Five winter cropping modes were set up, including winter fallow, winter Chinese vetch, winter rape, winter garlic and winter rotation (potato, Chinese milk vetch, rape). Soil carbon pool management index and comprehensive evaluation of different winter cropping modes were further analyzed by measuring nutrients, organic carbon, active organic carbon, and microbial biomass carbon in different soil layers. The results showed that the contents of soil organic carbon, microbial biomass carbon, soluble organic carbon and active organic carbon in different winter planting patterns were increased to a certain extent in the depth of 0-30 cm paddy field, compared with those in winter fallow treatment. Among them, soil organic carbon increased by 6.12%-7.17%, active organic carbon increased by 13.56%-20.76%, microbial biomass carbon increased by 0.13%-14.34%, soluble organic carbon increased by 3.49%-19.15%, and soil active organic carbon efficiency increased by 6.74%-17.20%. Winter rotation (potato, Chinese milk vetch, rape) could significantly promote the accumulation of total organic carbon and soluble organic carbon in paddy soil. Different winter patterns increased soil carbon pool activity index and carbon pool index, and soil carbon pool management index increased by 14.37%-27.29%. Soil organic carbon was significantly correlated with active organic carbon (P < 0.01); soil carbon pool management index was significantly correlated with total organic carbon (P < 0.05), and there was a significant correlation between soil organic carbon and active organic carbon (P < 0.01). It can be seen that different winter planting patterns can increase soil organic carbon content and improve soil carbon pool management index. The winter rotation (potato, Chinese milk vetch, rape) pattern has the best comprehensive effect, followed by winter garlic planting pattern.