Correlation Between Soil Nematodes Community Structure And Fertilization Level In Mortar Black Soil Under Long-term Location Conditions

Soil nematode community structure can well express the health status of farmland soil ecosystem.Therefore,based on the long-term location test base of black soil in Mengcheng County,this paper studied the response of soil nematode community structure to long-term location fertilization by the changes of soil nematode total number,tropic group,ecological index and other characteristics.The soil fertility level and crop yield indexes under different fertilization conditions were analyzed,and the feasibility of using soil nematode community structure to characterize the soil health status of the black soil was discussed.The main results are as follows:(1)There were significant differences in the total number of soil nematodes under different fertilization conditions,and the total number of soil nematodes was different in different sections,with the distribution of 0 ? 20 cm > 20 ? 40 cm> 40? 60 cm.Layer in the same section,the total number of soil nematodes are closely associated with different fertilization treatment,total number of abandoned and long-term fertilization soil nematodes higher than that of no fertilizer treatment,organic inorganic fertilizer treatment of soil nematodes is significantly higher than the single fertilizer treatment,the total organic inorganic fertilizer treatment of straw with the total number of soil nematodes than manure with processing.(2)Nutritional groups of soil nematodes were different under different long-term fertilization conditions.With the increase of soil depth,the relative abundance of plant parasitic nematodes decreased from top to bottom.In the same profile layer,the relative abundance of plant parasitic nematodes treated with manure combined with manure was significantly lower than that treated with no fertilizer,and the relative abundance of bacteriophagous nematodes was higher than that treated with no fertilizer.(3)Soil nematode ecological index were different under different fertilization conditions.With the increase of soil depth,soil nematode evenness index,Wasleyska index,maturity index and enrichment index were also significantly decreased.Layer in the same section,fertilizer treatments of shannon diversity index,and evenness index,Wasleyska index and the concentration index was significantly higher than that of no fertilizer treatment,including organic and inorganic fertilizer treatment is significantly higher than the single fertilizer,organic and inorganic fertilizer treatment of manure with significantly higher than that of straw with processing.The maturity index of plant parasitic nematodes showed the opposite trend.(4)Soil fertility levels were different under different long-term fertilization conditions.Soil fertility gradually decreased from top to bottom with the increase of soil depth.In the same profile layer,the soil fertility of long-term fertilization treatment was higher than that of no fertilization treatment.The soil fertility of combined application of organic and inorganic fertilizers was higher than that of single application of chemical fertilizer.In the treatment of combined application of organic and inorganic fertilizers,soil fertility of combined application of manure was higher than that of combined application of straw,and the contents of soil organic matter,alkali-hydrolyzed nitrogen,available phosphorus and available potassium were also significantly higher than that of combined application of straw.(5)There were significant differences in wheat yield among different fertilization treatments for a long time.The wheat yield of fertilization treatment was significantly higher than that of no fertilization treatment,and its yield increased from 337.87% to534.24%.The crop yield of combined application of organic and inorganic fertilizers was significantly higher than that of single application of chemical fertilizer.In the combined application of organic and inorganic fertilizers,the crop yield of combined application of manure was significantly higher than that of combined application of straw.(6)Soil nematode community structure,Shannon diversity index,evenness index,Wasyloska index richness index,enrichment index,relative abundance of bacteria eating nematodes and relative abundance of omnivorous/predatory nematodes were significantly positively correlated with crop yield.The relative abundance,dominance index and maturity index of parasitic nematodes were negatively correlated with crop yield.Because of the significant correlation between soil nematode community structure and crop yield,the use of soil nematode community structure can more accurately indicate crop yield.Therefore,it is feasible to use the change of soil nematode community structure to characterize the soil health status of the black soil.