Effects On Soil Microbial Under Organic Fertilizer Addition And Chemical Fertilizer Reduction

In order to explore the effects of chemical fertilizer reduction with organic fertilizerapplication on soil microbes, Wheat-soybean was planted under different fertilizer treatments,4chemical fertilizer(NPK) levels of100%,70%,50%,30%, and three organic fertilizer(M)level of18000,25000and34500kg·km-2(representing with LM, MM and HM, respectively)were seleted in the experiment with single NPK application as CK. In the treatments with100%NPK, the explicating amount of urea, diammonium phosphate and potassium sulfateper hectare were251.8,255.7and375.2kg·km-2, respectively. And collected0～20cm,20～40cm soil during in wheat seedling, wintering, jointing, maturity and in soybean fowering,pod, drum, maturity. In conclusion, the objective of our study is to investigate the effects ofseven different fertilization regimes and eight different sampling stages on soil water, cropyield and soil microbial properties. The main results are as follows：(1) The correlation among Soil enzyme activity， Micro-flora analysis, Soilmicrobial biomass carbon and nitrogen, Soil respiration is the significant, it can be used asevaluation index of soil fertility and soil quality. Different fertilization strategy hadsignificantly effects on index of Microbiological Characteristics, especially the organicfertilizer application influence is more obvious on Soil respiration, Soil microbial biomasscarbon and nitrogen, Soil enzyme activity and Micro-flora analysis. In comparison withCK, with the increase of organic fertilizer inputs, the effect is more and more obvious underthe condictions of zero chemical fertilizer reduction, the among Soil respiration, Soil microbialbiomass carbon and nitrogen, Soil enzyme activity and Micro-flora analysis had reached themaximum in the treatment of NPK+HM. The effect on Microbiological Characteristics of50%NPK+MM is more appropriate than the other treatments in the fertilizer reduction withorganic fertilization treatments, it showed that Moderate fertilizer reduction and with organicfertilizer can promote soil Microbiological Characteristics of each index increased, help toimprove soil fertility and increase crop yields.(2) Different fertilizer with Soil enzyme activity， Micro-flora analysis, Soil microbial biomass carbon and nitrogen, Soil respiration of wheat and soybeans with thechanges of the various growth are showed seasonal differences, but the same fertilizertreatments in different wheat and soybean growth period of change trend are basically thesame. Soil respiration, Soil microbial biomass carbon and nitrogen, Soil enzyme activity andMicro-flora analysis fall down to the minimum in wheat wintering stage and reached tomaximum in maturity. Soil respiration, Soil microbial biomass carbon and nitrogen, Soilenzyme activity and Micro-flora analysis change vary slightly in the soybean growth period,soil breathing quantity with the same fertilizer treatments in soybean reach maximumflowering, minimum at maturity; SMBC, SMBN with soybean growth as curve of “V” changetrend, drum of the microbial biomass is much smaller than other various period, until thematurity to rise significantly, achieve maximum; as for the number of microbial, differentfertilizer had no significant effect on fungal in soybean growth period, but the samefertilization with bacteria, actinomyces, the number of Kentucky in different growth stages ofsoybean change laws are consistent, it showed had been rising, maturity to achieve maximum.(3) Soil depth affect the Soil enzyme activity，Micro-flora analysis, Soil microbialbiomass carbon and nitrogen, Soil respiration are also significant differences, that isdegressive with soil deepen. Soil Microbiology characteristics of each index on0-20cm aremore significant than20-40cm under different fertilizer treatments. Deep in the soil,reasonable fertilization system can promote Soil enzyme activity，Micro-flora analysis, Soilmicrobial biomass carbon and nitrogen, Soil respiration rise, to increase plant root biomassand the secretion and the growth or breeding of microorganism, and can improve soil deepenvironment.(4) The trends of soil water are almost the same in different crop growth period,showing a decreasing trend with soil depth arden. Compared with the CK(single NPKapplication), application of organic fertilizer significantly increased soil water, and under thecondictions of zero chemical fertilizer reduction, soil water increased with the quantity oforganic manure, NPK+HM gave the best result thus, applying organic fertilizer canimprove the condition and the water retentivity of soil; soil water content of50%NPK+MM isthe highest in the fertilizer reduction with organic fertilization treatments, it showed thatmoderate fertilizer reduction with matching application of organic also could improve soilwater, help to improve the water retentivity of soil.(5) In comparison with CK, NPK+HM is the best in the condictions of zerochemical fertilizer reduction treatments,its yield of wheat and soybean increased by54.2%and32.8%, respectively compared with the treatments CK. Yield of50%NPK+MM is the highestin the fertilizer reduction with organic fertilization treatments, it showed that matching application of organic fertilizer can promote the growth and yield of crop, and fertilizer lessexcessive or insufficient organic fertilizer application are is not conducive to the improvementof crop yields.