Study On The Apply Governance Mechanisms Of Winter Replanting Rotation To Alleviate The Cropping Obstacles On Sweet Potato

In recent years,the area of specialized and industrial cultivation of sweet potatoes has been expanding,but the limited cultivated land resources and cultivation conditions have made the land replanting index continue to increase,and the continuous cultivation of sweet potatoes is serious.Long-term continuous cropping of sweet potato will lead to aggravation of soil-borne diseases and decrease of yield,so it is of great significance to solve the problem of obstacles to continuous sweet potato cropping.There are many reasons for the occurrence of continuous cropping disorders,among which soil microbial community changes are an important cause of continuous cropping disorders.Therefore,in this study,the sweet potato variety "Tobacco Potato 29" was used as the material,and the winter replanting rotation experiment was carried out with green manure pea(HRC023)and high sulfuroside rape(Yunqiao No.1),respectively,on the basis of clarifying the effects of the two winter replanting rotation treatments on the growth and root yield of sweet potato plants,taking the changes of soil microbial community as the starting point.The soil microbial regulation mechanism of two winter multicropping rotation patterns alleviating the obstacles of sweet potato continuous cropping was systematically analyzed.The main findings are as follows:1.Compared with the control treatment(CK),winter rotation pea treatment(PR)could significantly reduce the uniformity(Shannoneven index),diversity(Shannon index)and abundance(Chao index)of soil bacteria before sweet potato planting,and the soil bacterial community changed the most(community PCA distance was the farthest)from pre-planting to harvest,which significantly increased the proportion of Proteobacteria and Bacteroides in the soil before sweet potato planting.Winter rapeseed rotation(RR)could significantly reduce the diversity(Shannon index)and abundance(Chao index)of soil bacteria before sweet potato planting,and the soil bacterial community was the most stable(community PCA was the closest)from pre-planting to harvest,which significantly increased the proportion of actinomycetes and firmicutes at sweet potato harvest.2.Compared with the control treatment(CK),the winter rotation pea treatment(PR)significantly reduced the uniformity(Shannoneven index),diversity(Shannon index)and abundance(Chao index)of soil fungi before planting of sweet potatoes,reduced the proportion of ascomycetes in the soil of the pre-planting cultivation layer of sweet potatoes and increased the proportion of basidiomycetes,increased the proportion of ascomycetes in the soil of the cultivated layer at the time of sweet potato harvest and reduced the proportion of sporamus and basidiomycetes.Winter rapeseed rotation treatment(RR)had no significant effect on the Alpha diversity index of soil fungi before sweet potato planting,which reduced the proportion of ascomycetes in the soil before sweet potato planting,increased the proportion of ascomycetes and asporium in the tillage layer soil at the time of sweet potato harvest,and significantly reduced the abundance of pathotrophic and pathosaprotrophic fungi in the soil before planting and at the harvest of sweet potatoes.Both winter rotations increased the proportion of saprophytic fungi and symbiotic fungi in the cultivated soil at the time of sweet potato harvest.3.Compared with the control treatment(CK),winter rotation pea treatment(PR)and winter rotation rapeseed treatment(RR)promoted the growth of sweet potato plants,significantly increased the yield of potato nuggets at harvest and the commercial rate of potato nuggets,significantly reduced the starch content of potato nuggets,and increased the soluble total sugar content and sucrose content of potato nuggets to varying degrees.Among them,the winter rotation pea treatment(PR)significantly increased the fresh weight of the aboveground,fresh weight of the underground part,the length of the main stem,and the biomass ratio of roots and aboveground stems and leaves during 50 days of planting,and significantly increased the leaf area index and photosynthetic potential of potato seedlings when planted for 50 days and 120 days.Winter rapeseed rotation treatment(RR)significantly increased the fresh weight of aboveground,fresh weight and main stem length of potato seedlings after 50 days of planting,and had no significant effect on the biomass ratio of roots and aboveground stems and leaves after 50 days of planting,and significantly increased the leaf area index and photosynthetic potential of potato seedlings after 120 days of planting.Winter rotation pea treatment(PR)had the greatest effect on the growth of sweet potato plants.In 2021,the yield of tuber roots in winter crop rotation pea treatment(PR)and winter rotation rapeseed treatment(RR)increased by 9.27% and 6.56%,and the root commodity rate increased by 125.93% and 133.33%,respectively.In 2022,the yield of tuber roots in winter rotation pea treatment and winter rotation rapeseed treatment increased by24.09% and 19.17%,and the root commodity rate increased by 93.10% and 79.31%,respectively.