Effects Of Fertilization Treatment On Soil Microbial And Soil Fauna In Winter Wheat And Summer Maize Farmland In North China

In order to study the effect of the combined application of organic materials and chemical fertilization on the community structure of soil microorganism,nematode,meso-and micro-arthropod community in wheat-maize rotation field in fluvo-aquic soil region of North China.Field experiments with different fertilization treatments were set up in Ning-He district of Tianjin city.Some treatments were installed including 100% chemical fertilizer,100% bio-organic fertilizer,bio-organic fertilizer application with straw returning,combined application bio-organic fertilizer and chemical fertilizer(reduce 50% nitrogen fertilizer with straw returning,combined application bio-organic fertilizer and normal fertilizer with straw returning,combined application bio-organic fertilizer and chemical fertilizer(increase 50% nitrogen fertilizer)with straw returning.In this experiment,the effects of different fertilization treatments on the community structure and ecological index of soil microbes,soil nematodes,meso-and micro-arthropods were studied by Biolog-ECO microplate technology and soil animal morphology identification.The research contents and results were as follows:1.The changes of average well color development(AWCD)values of wheat season were between 0.55 ~ 1.13,and the value of bio-organic fertilizer + reduced fertilizer + 100% straw returning treatment was the highest.The AWCD values of the corn season ranged from 0.34 ~ 0.87,and the value of bio-organic fertilizer + incremental fertilizer + 100% straw returning treatment was the highest.Soil microbes had different utilization of carbon sources in different fertilization treatments.The relative utilization rate of sugar was the highest,44.58% ~ 51.70% in wheat season and 37.41% ~ 49.89% in maize season.The combined application of chemical and bio-organic fertilizer with straw returning could increase the AWCD value,and the AWCD value of 100% straw returning treatment was increased faster.The combined application of chemical fertilizer,bio-organic fertilizer and straw improved the activity of soil microbial community,increased the diversity and richness of soil microbial community,and was beneficial to maintain the metabolic activity and functional diversity of soil microbial community.2.During the whole investigation period,35 genera of soil nematodes were identified in the wheat season,and 26 genera were identified in the maize season.A total of 9 genera were same in the wheat and maize seasons.The combined application of bio-organic fertilizer and chemical fertilizer increased the total number of soil nematodes.The combined application of bio-organic fertilizer,chemical fertilizer and straw increased the number of dominant species of soil nematodes,which was conducive to the reproduction of omnivores-predators nematodes.With increasing chemical fertilizer and straw,the number of bacterivores nematodes increased,and the number of plant-parasites nematodes decreased.According to the analysis of the nematode ecological index,the soil organic matter was decomposed by bacterial pathway in all treatments.Bio-organic fertilizer + normal fertilizer + 100% straw returning could increase the number of nematode,improve the diversity of nematode species,and reduces the degree of interference of nematode by enhancing the stability of its food network.3.A total of 3,066 soil meso-and micro-arthropods were obtained during the whole investigation period.The total number of meso-and micro-arthropods in the maize season was higher than that in the wheat season.Acariformes and Collembola is dominant order.The effect of bio-organic fertilizer application and straw returning on the number of meso-and micro-arthropods was significant.Compared with different fertilization treatments,the addition of straw could affect the community structure of arthropods in meso-and micro-arthropods.The combined application of bio-organic fertilizer + normal fertilizer + 100% straw returning could increase the diversity and richness of mesoand micro-arthropod community,and was more conducive to the stability of meso-and micro-arthropod community.The combined application of chemical and bio-organic fertilizer with straw returning was more conducive to the stability of soil animal community structure.