Effects Of Rotation Of Faba Bean On Soil Microbial Community And Diversity In Potato Ridge-mulching Continuous Cropping Soil

The furrow-ridge and plastic mulching planting patterns can improve the soil micro-ecological environment and the soil water-heat ecological effect,the effects on soil nutrient,enzyme activity,microbial community and diversity are obviously different from the traditional planting methods.Rotation is an effective way to maintain the balance of soil habitat,but the bioremediation of soil microbial community diversity and soil quality has not been systematically studied under continuous film mulching cropping.The study was conducted on potato test field with mulching continuous cropping for 5 years in semi-arid region of Gansu province through the traditional methods of agrology,microbiology and high throughput sequencing,the effects of different film covering mode(nonfilm-mulched flat plot-CK,half-mulched ridge plot-T1,fully mulched ridge plot-T2)and cropping system(potato-potato-C and potato/broad bean-R)on soil nutrient,enzyme activity,microbial community and diversity were studied as follows:1.Compared with continuous cropping soil of potato,the content of soil available nitrogen,phosphorus and potassium of 2 kinds of film mulching patterns were improved differently,but the p H value of rotation decreased obviously.Besides,the improvement of half-mulched ridge plot on soil nutrients was obvious.The yield of mulching potato and broad bean was increased differently,the increase rate was 58.03%~73.47% and 70.37%~80.19%,and fully mulched ridge plot could increase the yield and economic benefit greatly.2.The soil enzyme activity was improved by film mulching+rotation.Overall,the activity of soil urease was decreased significantly from June to July.Specifically,in flowering stage of potato / flowering stage of broad bean(June),rotation had a great influence on soil urease activity,but had no significant effect on soil urease activity in July.The activity of catalase,alkaline phosphatase,invertase and protease enzyme in soil was increased significantly under film mulching+rotation from June to July with the increase of 3.57~9.67,1.58~1.93,1.04~2.57 and 0.61~2.84 times of continuous cropping system.3.The quantity of soil bacteria,fungi and actinomycetes in June was significantly increased by rotation.In June and July,the quantity of bacteria with T1 R and CKR was the largest.The quantity of fungi was significantly increased by T1 R and T2 R in June,but with the extension of growth period,there was a significant increase in continuous cropping soil with the same film-mulching model.The bacteria / fungi value of the rotation system was higher than that of continuous cropping in the same film mulching mode.The fully mulched ridge plot was more beneficial to the increase of soil actinomycetes than that of half-mulched ridge plot and nonfilm-mulched flat plot.4.The quantity of physiological function groups was increased under film mulching+rotation,but the effect of continuous cropping and rotation on the quantity of azotobacter,anaerobies azotobacter,nitrifying bacteria,denitrifying bacteria and ammonifying bacteria were different.The fully mulched ridge plot plays an active role in increasing the quantity of above bacterial groups.5.The Chao1,ACE and Shannon of soil bacteria were improved by film mulching+rotation and the ACE,Simpson and Shannon of soil fungi were improved by nonfilm-mulched/fully mulched ridge plot+rotation.Therefore,the diversity of soil bacteria and fungi was increased by rotation compared with continuous cropping.6.The ratio of dominant bacteria phylum(Proteobacteria)in fully mulched ridge plot was higher than that in half-mulched ridge and nonfilm-mulched flat plot.The bacteria dominant genus(Arthrobacter and Planctomyces)were obviously aggregated in the rotation system,however,Streptomyces,Steroidobacter and Lysobacter were enriched in the continuous cropping soil,and the half-mulched ridge plot had great influence.7.The dominant phylum of fungi is Ascomycota,and the ratio was increased by film mulching in continuous cropping system,among them,the relative abundance of the dominant genus(Monographella,Humicola and Fusarium)in the continuous cropping system is higher than that of the rotation system,while Mortierella and Acremonium are enriched in the rotation soil.And the effects of different mulching methods on the abundance of the fungi were different,the relative abundance of Humicola and Mortierella was higher in fully mulched ridge plot,while the relative abundance of Monographella and Acremonium was higher in the nonfilm-mulched flat plot,Moreover,the relative abundance of the Fusarium is higher than rotation in the continuous cropping system with nonfilm-mulched flat plot and fully mulched ridge plot.