Effects Of Fertilization Regime And Straw Returning On Soil Fauna In The Fluvo-aquic Soil

With the use of chemical fertilizers,the output of crops increase greatly,but it also brought many potential hazards.The straw that has plenty of nutrient elements necessary to plant,are direct utilization of renewable resources.In order to reduce the burden of soil and realize the sustainable development of agriculture,organic manure and straw returning were widely used.While they provide fertility for soil,more and more attention has been paid to the effects of soil health.Soil fauna,as an indicator of soil health,can reflect environmental conditions by changing its numbers and species.It will provide a scientific basis for further understanding the conservation function and maintenance mechanism of soil fauna under different farmland management measures in North China,as well as using soil animal community characteristics to evaluate soil quality and environmental safety.The main contents and results were as follows:1.Effects of different fertilization regimes on soil nematodes community: The results showed that Helicotylenchus,Acrobeloides,Eucephalobus were dominant genera in the study.Analysis of variance indicated that the total nematode density was no significant difference in the treatments(P>0.05).Appropriate amount chemical fertilizer promoted the nematodes,trophic groups and species.But they had a decreasing trend with chemical fertilizer increasing in the organic manure plus synthetic fertilizer treatment.The ecological indices of nematodes also was lower.It suggested organic manure plus synthetic fertilizer was good for the amount of nematodes,but the more of chemical fertilizer was bad to the stable of nematodes.2.Influences of different fertilization regimes on soil meso-and microarthropod community diversity:A total of 1570 soil meso-and micro-arthropods were obtained in this survey,belonging to 5 classes,9 orders and 35 families.On the whole,fertilization increased the total numbers and species,and promote soil arthropods,significantly increased the diversity of soil animal in surface soil.It was beneficial to the stability of animal communities.However,too much chemical fertilizer could inhibit some soil animals and reduce soil animal species.In addition,higher content of chemical fertilizer could significantly reduce the evenness of soil animals.It suggested organic manure plus synthetic fertilizer was good for the amount of soil meso-and micro-arthropod,but the more of chemical fertilizer was bad to the stable of soil fauna.3.Impacts of long-term straw returning on soil nematode community:Returning corn straw improved the total number of nematode,the number of bacterivores,and the number of omnivores-carnivores,but there were no significant differences in soil nematode amounts among different return amounts of corn straw.We also found that straw returning increased Shannon-Wiener index,Evenness index,Nematode Channel Ratio,Wasilewska index of soil nematode,yet decreased Plant parasite index.Our study suggested that straw returning could improve nematode abundance,genus and the nematode food web stability,and then reduced the disturbance levels.However,there was no significant difference among the different returning amount of corn straw.4.Effects of long-term return of straw on soil meso-and micro-arthropod community diversity: A total of 2394 individuals were extracted and identified in plot.These individuals belonged to 7 classes,6 orders and 47 families.Isotomidae and Onychiuridae were the dominant groups in all the treatments.And the 18 groups were common groups,account for 64.83%.The 27 groups were rare groups,account for5.97%.Compared with the control,the straw returning to the field reduced the soil fauna groups,and the number of groups decreased with the increase of the amount of straw returning.In addition,the total number of soil fauna was reduced by straw returning,but there was no significant difference(P>0.05).Straw returning could increase Shannon-Weiner,Pielou,Margalef of soil fauna at 0-10 cm soil layer.The results suggested the straw returning was beneficial to the stability of the soil fauna community in the surface soil(0-10cm).