The Relationship Between Soil Microbial Diversity And Organic Mattercomponent Of Continuous Cropping Cucumber In Solar Greenhouse

Cucumber is one of the main crops in our country and continuous cropping obstacle has gradually affected the sustainable development of cucumber cultivation in China,therefore,cucumber 'Jinyou 30' was used as experimental material,combined Biolog technology to study the diversity of soil microbial community structure,and with the organic nitrogen classification method from Bremner,to explore the changes of soil microbial community structure and organic carbon and nitrogen in 17th continuous cropping cucumber soils and microorganism.This paper provides a theoretical basis for alleviating continuous cropping obstacles.The main conclusions are as follows:In soil cultivation cropping conditions,the growth index of cucumber plant was increased at first and then decreased during cropping time 1th-9th stubble,continuous cropping obstacles appear in 5th stubble after 1th cropping.Cucumber plant height and yield began to gradually riseunder continuous cropping showed that continuous cropping cucumber cyclically changes.In substrate culture conditions,the short time of continuous cropping of cucumber plant height,stem diameter,yield and soil cultivation as the continuous cropping time increased first and then decreased after 5th stubblein continuous cropping system.The soil total nitrogen(TN)accumulated with the extension of continuous cropping stubbles;there was no significant difference in soil total potassium(TK);The content of soil total phosphorus increased at first then decreased in early continuous cropping during 1th?9th stubbles andthere has significant difference 7th stubble and 3th stubble,the result showed that soil nutrient content of 7th stubble was significant unbalanced.Available nitrogen(AN)and available phosphorus(AP)increased in the early stage then maintain stable.There were significant differences between 3th stubble and 1th stubble,and there was no significant difference after 3th stubbles.There showed a decreasing trend in pH,but the difference was not significant,the difference between the highest and the lowest value of 0.7 units,EC showed a decreasing trend but it was not significant,the difference between the maximum and the minimum was 0.12 mS/cm.Shannon-wiener index(H),carbon use source richness index(S)in soil and substrate microbe were significantly affected by continuous cropping,they were both increased first and then decreased soil under continuous cropping in continuous cropping period(1th?9th stubble,11th?17th stubble),showed a wave shape change.The diversity index was consistent with the continuous cropping time in substrate condition,but it was higher than that of soil.The results showed that the microbial activity in substrate condition was stronger.The content of readily oxidized organic carbonin the soil and substrate increased significantly with the extension of continuous cropping time,and the overall trend showed a decreasing trend after 5th stubble cropping,but there was no significant difference between each stubble after the 5th stubble;The content of Ammonia nitrogen,Amino acid nitrogen,Amino sugar nitrogen and Acidolysis unknown nitrogen increased with the increase of continuous cropping time,But the Ammonia nitrogen and Amino acid nitrogen in the acid solution of the proportion of total nitrogen decreased with increasing time while proportion of Amino sugar nitrogen and Acidolys is unknown nitrogen in total nitrogen increased with the increase of continuous cropping time.The same phenomenon is also reflected in the substrate continuous cropping,this shows that continuous cropping increased the organic nitrogen components,but changed the organic nitrogen component proportions.The main source of amino sugar nitrogen is microbial cell material,so it can be inferred that the metabolic activity of microorganisms increased with the continuous cropping time.The microbial diversity showed positive correlation with total carbon and ammonia nitrogen,amino sugar nitrogen in organic nitrogen components,this indicated that microbial community diversity improved with the increase of soil nutrients.Regression analysis showed that soil total carbon and readily oxidizable carbon are factors which have a direct influence on the microbial community diversity.In summary organic matter components is an important factor leading to the changes of microbial community diversity.