Effects Of Biochar On Soil Micro-Ecological Environment And Growth Of Cucumber In Different Continuous Cropping Of Greenhouse

In northern China,facility cucumber cultivation is common.With the increase of continuous planting years,the soil structure of the facility has been seriously damaged.The secondary salinization and continuous cropping obstacles have become more and more serious,which not only affects the growth and development of vegetables,but also restricts the agriculture of facilities.sustainable development.As a new type of soil improvement material,biochar has obvious effects on the improvement of continuous cropping soil,but the mechanism of action needs further study.This experiment was carried out in the solar greenhouse of No.1 Horticultural Experimental Station of Hebei Science & Technology Normal University.It was cultivated in plastic buckets,using cucumber as a test material,and the open field vegetable soil and the different continuous cropping cucumbers that had never been planted outside the greenhouse.The soil in the greenhouse was used as the tested soil.Two experiments of biochar application and continuous application were carried out to investigate the growth traits,yield per plant,fruit quality,soil physical and chemical properties and soil enzyme activity of cucumber plants with different continuous cropping years.And the influence of microbial diversity,etc.,in order to provide theoretical support for the application of biochar as a continuous soil amendment in production.The main findings are as follows:1.In the single application experiment of biochar,the application of biochar promoted the growth of cucumber plants in the continuous cropping soil of cucumber for 6 years and 10 years,improved the leaf structure,significantly increased the thickness of the leaves,and improved respectively.21.92% and 32.63% significantly increased the activity of leaf peroxidase,which increased by 25.39% and 10.72%,respectively,increased the content of cucumber protein and vitamin C(VC),and the protein content increased by 22.74% and 5.51%,respectively.The VC content increased by 4.65% and 5.13%,respectively,and the yield per plant of cucumber increased by 11.36% and 84.48%,respectively.The effect of biochar application onthe soil yield increase of 10 years was more than that of continuous soil for 6 years.2.For the continuous cropping of 6-year and 10-year cucumber greenhouse soils,the single application of biochar significantly improved the soil physical and chemical properties,and the soil bulk density decreased by 23.70% and 18.12%,respectively,and the organic matter content increased by 17.05% and 14.16%,respectively.The cation exchange capacity(CEC)increased by 10.66% and 21.01%,respectively;significantly increased the number of soil bacteria and bacteria/fungi.The number of bacteria was 1.13 and 2.00 times that of the same year,and the bacteria/fungi were the same as the soil for the same year.1.89 and 3.64 times,reducing the number of fungi,especially the number of Fusarium oxysporum,which are 1.81 and 1.79 times of continuous soil in the same year,which significantly reduced urease activity,enriched microbial diversity,improved microbial growth environment,and slowed down.The continuous cropping obstacle to cucumber.3.In the continuous application of biochar,for the continuous application of7-year and 11-year cucumber greenhouse soils,the continuous application of biochar promoted the growth of cucumber plants and improved the leaf structure,respectively.The increase of 22.19% and 1.66% reduced the content of malondialdehyde(MDA)and increased the activity of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT),among which POD and The activity of CAT reached a significant level,POD activity increased by 28.81% and 17.51%,respectively.The activity of CAT increased by 12.60% and 42.12%,respectively,and the yield per plant and fruit quality of cucumber increased.The yield per plant of cucumber increased by 6.31%.And 19.68%,the soluble sugar content increased by 14.84% and 16.36%,respectively.The continuous application of biochar was more effective than the single application for 11 years of continuous cropping.4.For continuous cropping of 7-year and 11-year cucumber greenhouse soils,the continuous application of biochar significantly improved the physical and chemical properties of the soil,and the soil bulk density decreased by 14.02% and 6.62%,respectively,and the organic matter content increased significantly.Increased by16.41% and 11.61%,CEC has also been significantly improved,increasing by 2.85%and 2.30%,respectively,increasing the number of soil bacteria and bacteria/fungi,inwhich bacteria/fungi are the same time continuous soil for single application of biochar The 1.75 and 1.72 times significantly reduced the number of fungi,which decreased by 28.99% and 31.93%,respectively,which enriched the microbial diversity,indicating that the continuous application of biochar in continuous cropping soil has better physical and chemical properties,and is more conducive to the absorption of nutrients by roots.It can significantly improve the ecological environment of cucumber continuous cropping soil.In summary,a single application of biochar reduces the soil bulk density,increases soil permeability,increases soil pH and CEC,enhances the availability of nutrients such as soil available phosphorus,reduces the number of soil fungi,and increases bacteria./Fungi,increased microbial uniformity index,richness index,enriched microbial diversity,improved root micro-ecological environment,promoted cucumber growth,increased cucumber yield per plant;continuous application of biochar was applied in a single application The effect of cucumber growth promotion is more obvious,which is mainly to improve the physical and chemical properties of the continuous cropping soil,enrich the microbial diversity,promote the growth of cucumber plants,improve the leaf structure of cucumber,reduce the content of MDA,and improve the activity of leaf protective enzymes.The yield and quality of cucumber per plant provided more nutrients for cucumber growth and improved the ecological environment of microbial root zone,which slowed the effect of continuous cropping on cucumber growth.