| Cucumber(Cucumis sativus L.)is one of the most widely cultivated greenhouse vegetables in China.The problem of continuous cropping,which leads to a decline in the yield and quality of greenhouse cucumbers and an imbalance in soil communities,has always existed and needs to be solved urgently.Straw returning is an effective agricultural measure to alleviate soil continuous cropping obstacles and promote the healthy and sustainable development of greenhouse vegetables.However,there have been no reports on the impact of corn green straw returning on the soil microbial community during continuous cropping of cucumbers.In this experiment,the effects of green corn straw returning on the changes in the root zone microbial community and cucumber growth were studied by setting up four different treatments using the cucumber variety ’Kangxiu No.4’.The goal was to provide theoretical and practical guidance for alleviating soil continuous cropping obstacles and achieving high-quality and safe cucumber production.The main results of the study are as follows:1.Straw returning treatments can reduce the bulk density of greenhouse soil,and the improvement in soil bulk density is significant after green straw tillage and mulching in the greenhouse;After mulching in the greenhouse and two seasons of cucumber harvesting,the total phosphorus,total nitrogen,and total potassium content of the soil under the green straw returning with mulching treatment were significantly higher than that of the control;The pH of the soil under different treatments had no significant effect on the greenhouse cucumber;The available nutrients under the green straw returning with mulching treatment were significantly higher than those of the control;Green straw returning combined with mulching in the greenhouse can improve soil fertility and act as a buffer,which is more conducive to the decomposition and release of nutrients from green corn straw,reducing fertilizer application and improving soil nutrient cycling and utilization;2.The diversity index of soil bacteria was increased after the green straw returning with mulching treatment;The dominant microbial compositions of the four treatments were similar at the phylum level,including Proteobacteria,Acidobacteria,Ascomycota,Basidiomycota,and Actinobacteria;At the genus level,the relative abundance of Chryseolinea,Urania-1B-19,and Nonomuraea increased significantly under the green straw returning with mulching treatment,which played a key role in the decomposition of the straw’s lignocellulose,thereby promoting the release of nutrients from the straw and improving soil fertility and bacterial communities;3.The diversity and abundance of fungi were slightly reduced in the green straw returning without mulching treatment and the green straw returning with mulching treatment,but the differences were not significant.The dominant fungal phyla of the four treatments were Ascomycota,Magnoliophyta,Chlorophyta,Zygomycota,and Basidiomycota;Further analysis showed that the green straw returning with mulching treatment significantly reduced the relative abundance of Mortierella,Fusarium,and Gibellulopsis,which to some extent changed the soil microbial community of greenhouse cucumbers during continuous cropping;4.The use of corn green straw mulching and film mulching for soil coverage significantly increased cucumber plant height compared to the control,to a certain extent improving the cucumber female flower rate and leaf number;The green straw returning with mulching treatment significantly increased the average fruit weight and yield per plant compared to the control,with a 28.80%and 24.71%increase in cucumber yield in the autumn of the same year and the following spring,respectively;The use of green straw mulching and film mulching helps the root system to absorb and utilize the nutrients in the soil,while ensuring the supply of materials needed for photosynthesis,promoting the synthesis,accumulation and transportation of photosynthetic products,and improving the yield of cucumbers. |
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