Effects Of Different Soil And Irrigation Water Treatment On Soil Characteristics,Microbial Diversity And Cucumber Quality

The scarcity of freshwater resources has become the main restrictive condition,and it has restricted the development of China’s industry and agriculture.How to solve the problem of China’s water resources crisis has become a very urgent task.However,brackish water,as a freshwater alternative resource,is one of the key ways to alleviate the water crisis.In this study,greenhouse cucumbers were used as experimental materials,fresh water,saline freshwater,and brackish water were treated with it,and two improved materials,earthworm compost and desulfurization gypsum were introduced to explore their effects on the physical and chemical properties of the greenhouse soil and the growth characteristics of cucumber,and reveal the corresponding laws of coordinated regulation between different irrigation and soil treatment,so as to provide theoretical support and technical guidance for the utilization of brackish water resources and the development of the greenhouse vegetable industry in Ningxia.Research indicates:(1)The mixed irrigation of brackish water and saline freshwater is not conducive to the soil water conservation,but through the treatment of desulfurization gypsum,earthworm composting plus desulfurization gypsum can enhance the soil water retention,which can effectively alleviate the water scarcity of crop rhizosphere under brackish water irrigation.(2)The brackish water treatment increased the EC value of the 0-40cm root layer soil,and reduced that of the root layer soil moisture content,bulk density,available potassium and organic matter content.(3)The application of earthworm compost under brackish water irrigation increased soil total nitrogen,total phosphorus,available phosphorus,available potassium,and organic matter content,and reduced soil bulk density;desulfurization gypsum increased the total nitrogen of 0-20cm soil,and total soil Phosphorus,available phosphorus and organic matter content of 20-40cm soil;the combined application of earthworm compost and desulfurization gypsum reduced soil bulk density and increased soil available phosphorus and potassium content.(4)Through brackish water irrigation,earthworm compost treatment significantly increased vitamin C,soluble sugar and cucumber yield,and reduced nitrate content;earthworm compost with desulfurization gypsum treatment increased cucumber vitamin C and yield.Under the condition of brackish water irrigation,the earthworm compost,earthworm compost with desulfurization gypsum treatment all significantly improved the cucumber vitamin C,soluble sugar,yield and freshness of the plant.(5)Compared with brackish water irrigation,brackish water irrigation increased the root length,root surface area and root tips,and the interaction between desulphurization gypsum and brackish water had positive effects on root growth and development.(6)Compared with fresh water irrigation,brackish water irrigation significantly increased the activities of catalase and sucrase,inhibited the activity of polyphenol oxidase without significant effect on urease and phosphatase.Brackish water treatment had a certain inhibitory effect on soil enzyme activity(except polyphenol oxidase).Under the condition of brackish and fresh water irrigation,earthworm composting place significantly increased soil enzyme activity,desulphurization gypsum treatment significantly increased catalase activity,earthworm compost with desulphurization gypsum treatment significantly increased urease and phosphatase activity.Under brackish water irrigation,earthworm composting increased the activities of hydrogen peroxide and sucrase,while earthworm composting with desulphurization gypsum had little synergistic effect.(7)In this study,MiSeq has employed the way of high-throughput sequencing,so as to sequence 12 bacterial populations of cucumbers that are tested with the rhizosphere soil.which has enriched the richness and diversity between the earthworm compost and desulfurization gypsum among the rhizosphere.(8)Compared with the number of soil bacteria,saltwater has been improved by 19.8%in terms of irrigation.Saltwater and freshwater can increase the number of microorganisms on the basis of the irrigation of saltwater.Thus,we can come to the conclusion that although the brackish water and saltwater mixed with irrigation are not good for the retention of the soil moisture,compared with fresh water irrigation,saltwater mixed with irrigation can still increasingly improve the quality and yield of protected cucumbers and has greatly contributed to the growth of roots of them.Besides,another advantage is stated as follows:the combination of earthworm compost and desulfurization gypsum is conducive to the quality and yield of cucumber and part soil enzyme activities.The linking of the earthworm compost and desulfurization gypsum has played an active role in soil microorganisms,It can improve the richness and diversity of soil bacterial community and increase the number of microorganisms.This study provides a theoretical basis for the sustainable production of protected vegetables and brackish water use in Ningxia.