| Increasing area of alkalinity in Songnen Plain limits the development of agriculture and animal husbandry severely, and the saline soil improvement in this area has become important task. The research was carried out at Zhaozhou country, Daqing City. The pH, salt content and soil enzyme activity for mulberry-soybean intercropping soil were detected to evaluate soil quality. The soil microorganisms were quantitated by dilution-plate method and the change of soil bacterial community structure were analyzed by Biolog microplates and Metagenomics. The study can provide theoretical basis for optimum model of mulberry-soybean intercropping and saline soil improvement. The results are as follows:The results of pH, content of salt and the soil enzyme activity for mulberry-soybean intercropping soil showed that pH for intercropping soil was significantly lower as compared with monoculture tend to neutral and intercropping decreased salt content of mulberry rhizosphere soil. The rhizosphere urease activity of mulberry-soybean intercropping was higer than monoculture. The soil catalase and alkaline phosphatase of intercropping were also higher as compared with monoculture. With the intercropping improving the soil qulity, the enzyme activities were promoted. There was no significantly difference in soil sucrase between intercropping and monoculture. The soil microbial quantity of the three categories can reflect changes in soil environmental quality, which indicated intercropping had a great impact on the soil microbe quantity. Compared with the monoculture, intercropping has increased the total number and proportion of the of bacteria and actinomycetes microorganisms. However, the quantity of fungi has not changed significantly. The results demonstrated that the bacteria and actinomycetes had more sensitive to intercropping and the mulberry-soybean intercropping had impact on the proportion of microbial communities with increasing the number of microorganisms.Using the Biolog technique, we investigated the effects of mulberry-soybean intercropping on the microbial community diversity of rhizophere soil in saline-alkaline soil. The results showed that the average well color development (AWCD) of intercropping was significantly higher than mulberry-soybean sole cropping. AWCD was highest in intercropping soybean and the lowest in sole mulberry with the incubation time. Compared with sole cropping, intercropping had less effect on Shannon diversity index and Simpson diversity index, but increased McIntosh index, which indicated that intercropping changed microbial community composition and enhanced microbial community diversity of rhizophere soil in saline-alkaline. Principal component analysis (PCA) showed that carbon utilization by soil microbial communities was different between intercropping and sole cropping, and carbohydrate, carboxylic acid and polymers played important roles in the differentiation of carbon sources, which indicated that plant ecological diversity of mulberry- soybean intercropping improved soil microbial community diversity.Soil bacterial16S rDNA diversity differences of mulberry-soybean intercropping and monoculture cropping were analyzed by using454pyrosequencing technology to explore the impact of intercropping on soil bacterial community structure diversity. The results showed that the richness index (Chao1and Ace) and diversity index (Shannon and Simpsion) of intercropping mulberry were higher as compared with monoculture, and the richness index of intercropping soybean were higher than monoculture relevantly. This demonstrated that the intercropping pattern can increase the microbial community diversity. The order of taxa percentage at phylum level were as follow: Proteobacteria> Acidobacteria> Actinobacteria> Chloroflex> Bacteroidetes> Planctomycetes> Gemmatimonadetes. Intercropping pattern has changed soybean rhizosphere bacterial community with impacting on mulberry rhizosphere microbes. Main show is that intercropping changed the abundance distribution of each cluster in community and increased some special flora with increasing the functional diversity of carbon metabolism and changing the bacterial community structure. Therefore, intercropping pattern has decreased soil pH and salt content in soda saline-alkali land with the increasing soil microbial community diversity significantly... |
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