Effects Of Different Disturbances On Leymus Chinensis’s Culm And Its Rhizosphere Soil Nematode Communities And Nematodes Flora

In 2015, under different disturbances, Leymus chinensis’s culm and its rhizosphere soil nematode species (genus), nematodes index,nematode flora, soil physical and chemical properties of typical grassland in XiLin Gol league’s Xelon chagan Banner were studied.The results showed:1. different types of disturbances effect Leymus chinensis’s culm and its rhizosphere soil nematode species composition,trophic groups of typical grassland.10 orders,23 families,58 species (genus) of soil nematodes in Leymus chinensis’s rhizosphere were captured,and 1557/100 g dry soil of them belongs to fungi-feeding nematodes (FF),and 5822/100 g dry soil of them belongs to plant parasitic nematodes (PP),and 12862/100 g dry soil of them belongs to bacteria-feeding nematodes (BF),and 2356/100 g dry scil of them belongs to predator/omnivorous nematode (OP).4 kinds of trophic groups were significantly different (P<0.05) among different treatments; Bacteria-feeding and predatory/omnivorous nematodes in fenced plot was significantly higher than the surrounding residential areas (P<0.05).The number of Plant parasitic nematodes in the surrounding residential areas and grazing areas were significantly higher than the enclosed area (P<0.05).Nematode species (genus) and number in Leymus chinensis were:the surrounding residential areas> fenced area> grazing area.2.Different disturbances affect Leymus chinensis’s rhizosphere soil nematode species and dominance.44 genera of nematodes were captured in the fenced area,dominant genus were Rhabditis,Acrobeles, Aporcelaimus,Geomonhystera,Wilsonema; 39 genera of nematodes were captured in the surrounding residential areas,dominant genus weteRhabditis, Arcobeloides, Aglenchus, Gracilacus,Tylenchorhynchus; 45 genera of nematodes were captured in grazing area,dominant genus were Aphelenchus Bursaphelenchus, Miculenchus, Rotylenchulus, Rotylenchus, Eudorylaimus. dominant genus within fenced area belongs to bacteria-feeding and omnivores predacious nematodes, dominant genus in the surrounding residential areas and grazing area were plant-parasitic nematodes.3. Different disturbances affect the distribution of nematodes Flora and community diversity index in rhizosphere nematodes,Maturity index (MI) and WI index in the surrounding residential areas and grazing areas were significantly lower than the enclosed area (P<0.05),the ratio of plant-parasitic nematodes index (PPI) and free-living nematodes and plant-parasitic nematode maturity index (PPI/MI) was significantly higher than the enclosed area.Soil nematodes in fenced area located in Area A,which showed that soil food web tend to be fungal degradation pathway, non-disturbance, and food web is stable,soil nematodes in surrounding residential area distributed Area C (0-10cm soil layer).Area D (10-20cm soil layer):showed that soil nutrient poor food web tend mainly to be bacterial degradation and to be a high degree of interference or coercion, food webs become instability or degradation.Soil nematode in grazing area distributed Area D (0-10cm soil) and Area B (10-20cm soil layer):the condition of s soil nutrients is better or worse, food webs is fungal degradation or degradation balance,the degree of interference is low or moderate.4. different types of disturbances effect Leymus chinensis^s morphology, biomass and soil properties. Leymus chinensis’s culm height,leaf length and width, root length, weight of Leymus chinensis’s culm, leaf weight, stem weight and root weight in fenced area was significantly higher than residential around and grazing areas (P<0.05);Organic carbon, available P and K in fenced area and grazing area,were significantly higher than the surrounding residential (P<0.05). pH value in fenced area is higher than surrounding residential (P<0.05).5.There was a significant negative correlation between Leymus chinensis’s roots length and structure index (SI).There was a significant negative correlation betweenroot weight and Wasilewska index (WI), nematode channel ratio (NCR), (P<0.01 or P <0.Q5).There was a significant positive correlation between root weight and nutrition group index (TD), plant-parasitic nematodes index (PPI), the Channel Index (CI) (P<0.01 or P<0.05).There was a significant negative correlation between.soil pH value and Leymus chinensis’s roots length, root weight, leaf weight (P<0.05). There was a significant positive correlation between soil available nitrogen content and Leymus chinensis’s roots weight (P<0.01).