The Influence Of Different Grazing Intensity To Typical Grassland Soil Nematodes Communities

This study as the object of Xilin Gol Typical Steppe Nematode Community,Make a research to the soil Nematode Community structure, soil nematode species(genus)and quantity,diversity. Use the principal component analysis and canonical correlation analysis,get correlation analysis to soil nematode community,chemical properties and ground vegetation. Make a fuzzy comprehensive evaluation to soil nematode community indicators,Soil chemical properties and vegetation Index System. The main conclusion as follows:1. Grazing intensity affect the species(genus)and quantity of typical steppe soil nematodes:the capture results from xinlin Gol zhengxiangbaiqi shows its can classify to 28genus in the different grazing area.Respectively:BursapHelenchus,ApHelenchoides, Rotylenchus,Helicotylenchu,Tylenchorhynchus,AglenchusPratylenchus,Filenchus,Rhabditis ,Diplogaster,Tylenchus,Monhysterida,AlaimusMononchus,Longidorus,Malenchu,Trichodor us, Hoplolaimus,AcontylusMeagher HemicycliopHora, DolichorusParatylenchus, Criconema, Chromadorita, CepHalenchus.2. Grazing Intensity affect the soil nematode trophic groups:edible fungus nematodes are 1626insects/100g dry soil,plant parasitic nematodes are 6695 insects/100g dry soil,omnivorous predators nematodes are 781 insects/100g dry soil.Grazing intensity affect the total number and dominant genera of soil nematodes:in the fenced area is 3494insects/100g dry soil,ApHelenchoides and Tylenchus genus are dominant genera of nematodesy,Alaimus is the common one. Light grazing area is 3870insects/100g dry soil,Rhabditis and Tylenchus are dominant genera of nematodes.Moderate grazing area is 2993insects/100g dry soil,Tylenchus and Hoplolaimus are dominant genera of nematodes. Heavy grazing area is 2430insects/100g dry soil,Aglenchus and CepHalenchus dominant genera of nematodes, Tylenchus is the common one;There has difference between different grazing area soil nematodes(P<0.05).3. Grazing intensity affect the diversity index of soil nematodes;heighten the index of WI,MF/B,MI,λ,SI,EI,SR,and reduce the index of F/B,H,MI.4. Grazing intensity affect the ground vegetation and soil chemical properties:with the grazing intensity strengthen,the communities height,aboveground biomass,Pielou evenness and the index of dominance have increased then decreased trend;the communities density,community coverage,the index of species richness and Shannon-Wiener variety have decreased trend(P<0.05).With the increasing of grazing intensity,the soil organic carbon,available phosphorus and K were decreasing,pH was increasing;And soil organic carbon(0-10 cm soil),Available nitrogen,K,phosphorus and pH value have significant difference(P<0.05).5. Make a fuzzy comprehensive evaluation to the index system which consist of soil Nematodes,soil chemical properties and vegetation factor under the different grazing area;The indication of light grazing area was 0.8437,its means soil Nematodes,soil chemical properties and vegetation factor are 84.37% in the current fence of light grazing area;The indication of moderate grazing area was 0.7385,its means soil Nematodes,soil chemical properties and vegetation factor are 73.85% in the current fence of moderate grazing area;The indication of heavy grazing area was 0.7030,its means soil Nematodes,soil chemical properties and vegetation factor are 70.30% in the current fence of heavy grazing area.5. The indication of fuzzy comprehensive evaluation to the system which consist of soil nematode community indicators,soil chemical properties and vegetation shows that:the fenced area as comparison,light intensity area as stable rating,moderate intensity area as unstable rating,heavy intensity area as unstable rating;The four different rating Indication range are 1-0.8437;0.8437-0.7385;0.7385-0.7030;0.7030-0.