Abstract:

The effect of organic soil conditioner and compound microbial fertilizer on soil salinization and the response of the functional diversity of soil microbial communities to compound microbial fertilizer were studied in Zhaodong saline soil. Saline soil (0-30 cm depth, pH 9.05) from Zhaodong experimental forest farm in Heilongjiang Province was excavated and transported to an artificial soil pool for backfilling. Organic soil conditioner was first added to the soil pool to reduce the saline-alkali properties of the saline soil. 20 days later, three years old Lycium barbarum seedlings were planted and compound microbial fertilizer was applied in the germination period of Lycium barbarum. Three treatments were designed: the organic soil conditioner + fine yellow Streptomyces, organic soil conditioner + furfural residue, and organic soil conditioner + furfural residue + fine yellow Streptomyces, the control sample of soil was only added with organic soil conditioner. The soil samples were took in October of the same year, the basic chemical properties of soil were tested, and Biolog-ECO micro-plate method was applied to the determination of soil microbial community functional diversity. The results showed that the soil treated with organic soil conditioner decreased from pH 9.05 to pH 8.59, and the soil treated with compound microbial fertilizer on this basis decreased from pH 8.59 to pH 7.71. The value of electrical conductivity was significantly increased in the soil of compound microbial fertilizer containing furfural residue. The total nitrogen, total phosphorus, total carbon and organic carbon in the soil all increased after the application of compound microbial fertilizer. The soil color change rate (AWCD) and the utilization capacity of six carbon sources in the sample plot treated with compound microbial fertilizer were higher than those in the sample plot treated with organic soil conditioner alone. The evenness, richness and diversity index of soil microorganisms were higher under the application of compound microbial fertilizer than that under the application of organic soil conditioner alone. The relationship between the soil chemical properties and the microbial diversity response was significant after the application of compound microbial fertilizer. The pH value of saline soil could be significantly reduced while the organic soil conditioner and the compound microbial fertilizer were added, but the value of electrical conductivity could be increased. The ability of microorganisms using carbon substrates could be increased when compound microbial fertilizer were added, especially the ability of using amino acid and aromatic carbon sources.

Key words: saline soil, compound microbial fertilizer, soil microorganism, organic soil conditioner, microbial community diversity