Effects Of Different Fertilizing Treatments On The Microbial Flora In The Huang-Huai-Hai Area

A field experiment was carried out to analyse the effects of different fertilizing treatments on soilmicro flora of winter wheat/summer corn rotation system in the Huang-Huai-Hai area. The5treatmentswere marked as T1(no fertilizer control)、T2(NPK)、T3(70%NPK+organic fertilizer)、T4(NPK+straw) and T5(NPK+straw+inoculant). The compositional and functional diversity of soil micro floraanalyzed by DGGE and Biolog respectively, combined with other indicators, such as soil property、soilenzyme activity、microbial quantity and crop yield, were used to analyze the effects of differentfertilizing treatments on soil micro flora, the conclusion were aimed at constructing high yield soilmicro flora. The main research results were shown as follows:1. Effects of different fertilizing treatments on soil properties: there was no significant difference ofsoil pH value、organic matterin content under all treatments, but N、P、K content under fertilizingtreatments were slightly higher than those under control.2. Microbial quantities and the activities of soil urease、cellulase under fertilizing treatments wereall higher than those under control. Microbial quantities under T5increased up to70.9%during wheatseason and283.5%during corn season compared to control. The difference of activities of soil ureaseand cellulase between T5treatment and control reached a significant level (p<0.05) during the twoseasons.3. DGGE was used to analyse the microbial flora composition.10bands of wheat season and13bands of corn season were sequenced. The results showed that, the bacteria of the majority wereuncultured during two seasons. Bacillus sp. and Paenibacillus sp. were the most flora of culturedbacteria. The microbial community could be clustered into three groups during wheat and cornseasons. T1and T2were clustered into the first group, so were T4、T5into the second group, and T3into the third group.4. The results of functional diversity of soil micro flora analyzed by Biolog showed that, theAWCD value and the microbial community species diversity indexes (H、E) under T3、T4and T5were higher than those under T2and T1, while the results were just opposite to dominance index (DS).Principal component analysis showed that, the soil microbial metabolic capacity: T3> T4、T5> T2>T1. Correlation analysis showed that, Biolog indexes were related to the soil microbiologicalproperties to a certain degree.5. Compared with the crop yields under control, crop yields under fertilizing treatments weresignificantly improved. The wheat yield under T5treatment was the highest with a increase rate of38.2%, but T3treatment was best for the corn yield with a increase rate of29.2%. The number of wheattillers before winter under T3、T4、T5were higher than that under T2、T1, while there was no significantdifference of the maximum number of tillers among the treatments. Corn chlorophyll content (SPADvalue)、leaf area index (LAI) and dry matter accumulation under fertilizing treatments were higher thanthose under control, while the differences among the fertilizing treatments were not significant. Correlation analysis showed that, soil urease and soil cellulase could reflect soil fertility to a certaindegree.Above all, in the experimental conditions, the organic fertilizer treatment, and the straw returningtreatments were more conducive to build high yield soil microbial flora.