Effect Of Long-term Cucumber Continuous Cropping On Fungal Community Structure Diversity Of Soil In Solar Greenhouse

Cucumber is one of the main vegetable crops cultivated in China.Due to the specialization and intensive development of greenhouse vegetables,the obstacles to continuous cropping of vegetables have become increasingly serious,which has become the main limiting factor for the sustainable development of facility vegetables.Therefore,this test is to 'optimal 30 jin cucumber varieties as experimental materials,with the method of the soil seedling cultivation,continuous 1 ~ 23 in sunlight greenhouse cucumber continuous cropping stubble location test,the determination of phospholipid fatty acid method and the analysis of high-throughput sequencing technologies of microbial diversity of fungal community structure,research the sunlight greenhouse cucumber cultivation of long-term continuous cropping soil microbial species and diversity of fungal community structure,in order to explore the sunlight greenhouse cucumber under the conditions of continuous cropping soil obstacle mechanism lay the foundation.The mechanism lays the foundation.The main conclusions are as follows:1.The results showed that the dry matter accumulation,yield,p H value,EC value and available nutrients of cucumber plants in 1 ~ 23 stubble all changed in a wavy pattern,and there was no significant difference between them and the first stubble.2.Studies on soil microorganisms by phospholipid fatty acid determination showed that: All kinds of microbial contents showed wavy changes,showing a basic trend of first increasing and then decreasing.Except for the first crop(the first crop had the lowest microbial species),there was no significant difference in the microbial content between the other crops.However,with the increase of continuous cropping,all the indicators showed a decreasing trend,and the microbial content composition became more and more similar.In the microbial species cluster analysis and PCA analysis,the microbial content in the first stubble was significantly different from that in the other stubble,and in the remaining stubble,significant separation occurred in the 5th and 21 st stubble,and the microbial content in the remaining 9th,13 th and 17 th stubble was basically similar.3.Studies on the structural diversity of fungal communities using high-throughput sequencing technology showed that: The number of fungal species in cucumber continuous cropping soil showed similar wavy changes at the level of phylum to genus,among which the number of classes,orders,families and genera in the 2nd ~ 8th crop showed a decreasing trend.At the level of class and order,the number of 8 ~ 20 stubble showed an increasing trend.The number of families and genera increased at the 10 th crop and then decreased continuously.In the fungus Alpha diversity index,the richness and diversity of soil fungi in the 2nd ~ 8th stubble showed a continuous decrease,among which,the richness increased in the 10 th stubble and continued to decrease after that,but the diversity index showed a slow increase in the 10 th 14-20 th stubble.In the cluster analysis and PCA analysis,the structural diversity of the soil fungus community in the 2nd,6th and 8th stubble showed significant changes continuously.After that,the structural diversity of the fungus community in the 10 th,14th and 20 th stubble was basically similar,that is,the composition of soil fungi tended to be stable.To sum up,this experiment by sunlight greenhouse cucumber crop of 23 times of positioning test showed that continuous cropping greenhouse soil microbial species and the characteristics of the fungi species wavy change general soil microorganisms in continuous cropping stubble nine times before significant change happens continuously,after microbial presents a state of stable,basically not changed significantly with the increase of crop time continuous cropping.