Effects Of Organic And Inorganic Fertilizer Application On Nitrogen Transformation Biological Process In Drip Irrigation Cotton Field

【Objective】The relations between organic nitrogen components and soil nutrient with soil nitrogentransformation were studied to increase effective nutrient content different fertilizer treatments. The changeof soil microbial quantity and metabolic function diversity were evaluated to explore the relationshipbetween soil microorganisms and nitrogen transformation so as to promote the growth of beneficialbacterial, nitrogen transformation and nitrogen use efficiency with different fertilizer treatments. Therelationship between different nitrogen transformation and cotton yield were analysied to achieve highcotton yield and provide the basic theory for the scientific and rational fertilization.【Method】 Field experiment were carried out with treatments of control treatment(no fertilizer),chemical fertilizer, different ratios of combined application of organic and inorganic fertilizers and othertreatments on drip irrigation cropping cotton soil for three consective year in Xinjiang. The change of soilorganic nitrogen component, microbial-process, enzyme activity, functional microbial, microbial biomassnitrogen and cotton yield were studied in different years.【Result】(1)Organic and inorganic fertilizers significantly increased total nitrogen, phosphorus content,ammonium, nitrate, avaible phosphorus and potassium the content of soil organic nitrogen components andthe proportion of each component in total soil nitrogen, particularly amino nitrogen of acid solution andammonium nitrogen, both with microbial biomass nitrogen was significantly correlative.(2) Organic and inorganic fertilizers made for microbial growth and the number of functionmicroorganisms in soil.Compared with no fertilization, soil aerobic azotobacter, ammoniated bacteria,nitrifying bacteria and denitrifying bacteria in an average increase of0.48times,4.2times,3.0times,2.8times. However, chemical fertilizer would inhibit the growth of nitrogen-fixing bacteria.(3) Organic manure and chemical fertilizer could significantly impact the intensity of soilammonification, nitrification and denitrification intensity, compared with no fertilizer, ammonification andnitrification improved by12.0%and95.5%, denitrification only increased3.8%. Chemical fertilizer couldstrengthen the denitrification of the soil significantly.(4) Organic and inorganic fertilizers could improve soil enzyme activities, soil urease, invertase,protease, nitrate reductase and nitrite reductase decreased after the first and increased with the cottongrowing period, and microbial biomass nitrogen was not significantly with organic and inorganic fertilizerand chemical fertilizer treatment, and the increase with organic fertilizer increased.(5) Fertilization chould increase the cotton leaf chlorophyll content, nutrient absorbed and cotton yield.Cotton chlorophyll content decreased increased first and then decreased with the cotton growing period,and the increase was more obvious in the late fertilization.Cotton yield changed less in2th years after fertilization, but organic and inorganic fertilizers was higher of8.4%-16.4%than the chemical fertilizertreatment in3th years, and cotton yield was more higher with organic fertilizer increased, while nutrientabsorbed and cotton yield changed less.【Conclusion】(1) Organic fertilizer and chemical fertilizer application increased the content of organic nitrogen, andtotal nitrogen, total phosphorus and other nutrients, improved soil physical and chemical properties and soilfertility.(2) Organic fertilizer application had a certain role on soil microorganisms and their metabolites.Itshowed significant increase soil at the number of nitrogen-fixing bacteria, ammoniated bacteria, nitrifyingbacteria and denitrifying bacteria. Soil microbial activity, enzyme activity, soil ammonification, nitrificationand denitrification had increased, but chemical fertilizer improved soil denitrification strength. Organic andinorganic fertilizers also increased microbial biomass nitrogen content in soil, especially the soil nitrogenpool reserves more apparent increased with bio-organic fertilizer added.(3) Different fertilization increased leaf chlorophyll content, nutrient absorbed and yield, organic andinorganic fertilizers were more obvious in the late cotton growing.Thus, the combined application of organic and inorganic fertilizers was a effective means to improvesoil properties, soil fertility, yield and fertilizer use efficiency.