| Biogas is an important biological organic fertilizer with various nutrients. Biogas fertilizer can improve and promote the soil microbial community. This paper explored the effects of different fertilization treatments on soil microbial characteristics in wheat growing field in Chongzhou, and there were 6 treatments designed:no fertilizer (CK), chemical fertilizer only (NPK), mixed application of biogas fertilizer and chemical fertilizer (NG), low quantity biogas manure (G1), medium quantity biogas manure (G2) and high quantity biogas manure (G3). Five kinds of soil enzyme activities, soil microbial biomass carbon, soil microbial biomass nitrogen, soil microbial number and the bacteria diversity in different treatment soil was studied. The following results were gained.1. The soil phosphatase and chitinase activity varied significantly along with the different growth periods, and the phosphatase and chitinase activity in the elongation stage was the highest; however, it was the lowest in the harvest stage. The soil enzyme activity between different treatments was different obviously, and the phosphatase activity of treatment G3 got the highest in the harvest stage, which was 1003.29±80.03 μmol h-1 g-1; Chitinase activity of NPK treatment was the highest in the elongation stage, which was 38.87±3.46 μmol h-1 g-1. Soil catalase and polyphenol oxidase activity increased along with the increase of biogas fertilizer (treatments G1, G2 and G3); the catalase activity of treatment G3 was higher than the others in jointing stage and harvest stage, and was 12.62±0.21 μmol h-1 g-1 and 15.45±0.26 μmol h-1 g-1, respectively. Among all the growth stages, treatment NG had the highest amylase activity, and was 230.58±10.82 μg h-1 g-1 in harvest stage.2. The content of SMBC varied with the growth period of wheat, the average SMBC changed as the following order:jointing stage> harvest stage> seedling stage. SMBC of treatment G2 was the highest (1551.09±35.42 μg g-1) in the harvest time, and was the lowest (1023.27±65.33 μg g-1) in seedling stage. The SMBN varied with the different growth periods, and the SMBN was the highest in harvest period, was the lowest in seedling stage; of them, SMBN of G3 in harvest period was the highest, and was 73.74±7.96 μgg-1.3. The lowest soil bacteria amount was in the seedling stage, and the bacterial amount was 16.98×106 cfu g-1, and the largest amount was in harvest stage, and was 49.80×106 cfu g-1; The bacterial quantity of G1, G2, G3 and NG was significantly higher than that of treatment NPK and CK. The fungal quantity between treatments was different, and the fungal quantity of treatment G1, G2, G3 and NG was higher in seedling stage than that in harvest stage; however, the highest fungal number of treatment NPK and CK was found in seedling stage, and the lowest value was in harvest stage. The fungi number of treatment NPK was the highest in seedling stage, and was 36.75±1.61 ×104 cfu g-1; However, in the jointing stage and harvest stage, treatment G1 had the highest fungi amount. In seedling stage and jointing stage, actinomyces number of treatment NG was the highest, and was 213.11±34.17 ×105 cfu g-1 and 76.77±4.74 ×105 cfu g-1; In harvest stage, actinomyces number of G3 was the highest, and was 165.47±22.39 ×105 cfu g-1.4. A total of 184 bacterial strains were isolated from the soil, and analyzed by BOX-PCR and 16S rDNA PCR-RFLP, the results indicated that the genetic diversity was existed.16S rDNA sequence of representative strains was analyzed and the phylogenetic tree was constructed, the results showed that all strains formed four phylogenic branches, and genus Bacillus was the dominant one, and there different Bacillus species. Lysinibacillus strains were founded in seedling stage and jointing stage soil with fertilizer; Mircobacterium only appeared in the wheat jointing stage soil; however, Bacillus pumilus was isolated from harvest soil. |
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