Effects Of Maize Intercropping And Residue Returning On Soil Carbon Sequestration Capacity And Yield And Quality Of Fall Broccoli In Multiple Cropping System

Based on 6 years of long-term located farmland, this experiment was implemented in Zhangwangzhuang countryside in Laiyang county, Yantai city. With broccoli and waxy maize as research materials, we systematically studied the effects of 4 kinds of planting patterns(B/M-B:relay intercropping of broccoli and waxy maize; B-B: broccoli monoculture; G/M-B:relay intercropping of green sword bean and waxy maize; G-B: green sword bean monoculture) with 2 kinds of residue returning(residue returning and no residue returning) on soil carbon sequestration capacity and crop productivity. We comprehensively evaluated the effects of maize intercropping and residue returning on soil carbon sequestration capacity and crop productivity of multiple cropping vegetables through the studies of soil water stable aggregates and soil organic carbon, in order to establish a continuous improvement of the comprehensive benefits of multiple cropping vegetables.Soil organic carbon were very significant positive correlation with the easy oxidation of carbon content. The content of soil organic carbon and soil readily oxidizable carbon reached to the highest at vegetative period and the second peak at autumn vegetable harvest period.And the difference was significant between the periods. The content of soil organic carbon and soil readily oxidizable carbon in 0-10 cm soil layer is higher than that in 10-20 cm layer.Soil organic carbon and soil readily oxidizable carbon content of residue returning was higher than that without residue returning.The regression analysis also showed that there was a significant positive correlation between soil organic carbon and soil water stable aggregates(p<0.01). The content of soilmacro-aggregate in 0-10 cm and 10-20 cm was higher than that in 20-40 cm. The distribution of soil aggregate was gradually concentrate on decreasing particle size, narrow distribution range with increasing soil layer depth. Soil macro-aggregate content in vegetative period and autumn vegetable harvest period was higher than that in seedling period and ball-flower growth period. Soil macro-aggregate content of maize intercropping and residue returning was higher than others significantly and monoculture was the lowest. Soil macro-aggregate content of green beans treatments were higher than that of broccoli. Residue returning,intercropping and legumes had important influence on the formation and stability of soil macro-aggregates.The biology yield of maize intercropping and residue returning were higher than only intercropping and monoculture in Autumn. The biology yield of G/MR-B and G/M-B were significantly higher than that of G-B by 39.18% and 17.62%. And B/MR-B and B/M-B were significantly higher than B-B by 42.97% and 13.99%. The economic yield of maize intercropping and residue returning was higher than that of other treatments and the monoculture was the lowest. Residue returning provides a good soil environment for vegetable growth which improves the quality of the vegetable. Residue returning could increase Vegetable vitamin C, total phenolics, soluble sugar, soluble protein and free amino acid content significantly. Intercropping could increase total phenolics and free amino acid content significantly.The cropping pattern of intercropping with residue maintained a higher level of SOC pool. Under the condition of residue returning, the SOC pool of G/MR-B and B/MR-B were significantly higher than that of B-B by 66.35% and 60.90%. The SOC pool of G/M-B,B/M-B and G-B were significantly higher than that of B-B by 20.05%, 13.82% and 13.31%.The SOC pool of all residue returning were higher than that of no residue returning.In conclusion, residue returning could increase soil water stable aggregate and SOC pool content, improve the quality of vegetables, and increase the biological and economic yield of vegetables. Intercropping could increase soil water stable aggregate and the biological yield of vegetables. Residue returning with intercropping could increase soil water stable aggregate and SOC pool content, improve the quality of vegetables, and increase the biological and economic yield of vegetables significantly, which could improve the overall efficiency ofvegetable fields sustainable.