Study On Soil Nematode Community Characteristics In Rhizosphere Of Forage Grass

In this experiment,the community characteristics of soil nematodes in the rhizosphere of four forages were studied,which were Medicago varia Martin ‘caoyuan No.2’,Medicago sativa L.‘caoyuan No.4’,Agropyron mongolicum Keng cv.Mengnong No.1,Agropyron cristatum × A.desertorunm.cv.Mengnong,and further analyzed the relationship between soil nematode community and soil environmental factors.Then the key factors affecting the community characteristics of soil nematodes were discussed.Main research results and conclusions:(1)A total of 24 genera of soil nematodes were captured in the experimental area,and the number,species and dominant groups of four species of grass root nematodes were different.Agropyron mongolicum Keng cv Mengnong No.1 has the largest number of soil nematodes and the largest number of genera,22 genera.The dominant soil genera in the rhizosphere of the four forages are bacterial eating nematodes,which are Acrobeles,Cephalobus and Cervidellus respectively,and the relative abundance of the dominant genera in the rhizosphere of each forage is different.(2)The community structure of soil nematodes in the four grazing grasslands is different,and there are differences among the root circumference of each pasture.From the perspective of trophic groups,the number of bacterial eating nematodes was the largest in the four forage types,and the least was omnivorous predatory nematodes,while the number of fungal eating nematodes and plant parasitic nematodes varied with the types of forage types;From the perspective of C-P groups,c-p2 groups of soil nematodes around the roots of the four forages account for the highest proportion,while c-p5 groups are the least,and the proportion of other groups is different.(3)The diversity of soil nematodes was different in the root circumference of the four forages,and the change trend was inconsistent.Among them,Medicago varia Martin‘caoyuan No.2’ nematode has the highest metabolic footprint and the richest diversity.(4)The ecological indexes of four forages were different.In terms of comprehensive ecological index,the soil health status of Medicago varia Martin‘Caoyuan No.4’ is relatively good.(5)Based on the results of redundancy analysis(RDA)of soil nematode community genera,soil physical and chemical properties and microbial biomass carbon and nitrogen contents in different forage plots,water content and available potassium content have a great impact on the species composition of soil nematode community.The above conclusions show that Planting Different Forages on relatively consistent soil will have specificity in the characteristics of soil nematode community around different forages.Therefore,it is necessary to master the impact process of planting Forages on soil nematode food web and soil ecosystem when establishing artificial grassland.