Abstract:

Soil microbial diversity is one of the important factors to improve soil productivity in planted forests. Due to the serious soil degradation of the second-generation Poplar forest and with the aim of improving the soil microbial diversity of degraded land and finding out the suitable ratio of fertilizer solution, 5-year-old second-generation Poplar forests in northern Anhui were used as the study objects. After 4 consecutive years of fertilization experiment, soil samples were collected, and high-throughput sequencing technology was used to analyze the change characteristics of soil microbial communities in Poplar forests under different fertilization treatments with an RDA analysis of environmental factors. The results showed that the MND1, Gaiella, Pirellula and RB41 were the dominant bacterial genera in the second-generation Poplar forest, and there were significant differences of bacterial genus between fertilized soil surface and unfertilized soil. Lecanicillium, Mortierella and Fusarium were 3 dominant fungal genera and the distribution of fungal communities in the soil layer was less relevant. Application of nitrogen fertilizer 250 g/plant, phosphate fertilizer 500 g/plant, organic fertilizer 500 g/plant and soil improvement biological bacterial fertilizer 200 g/plant and application of nitrogen fertilizer 125 g/plant, phosphate fertilizer 500 g/plant, potash fertilizer 75 g/plant and soil improvement biological bacterial fertilizer 100 g/plant had a more uniform distribution and higher diversity of bacteria in the surface soil, and were suitable for improving the diversity of forest surface soil bacterial community. Application of nitrogen fertilizer 500 g/plant, potash fertilizer 75 g/plant, organic fertilizer 500 g/plant and soil improvement biological bacterial fertilizer 150 g/plant and application of nitrogen fertilizer 250 g/plant, phosphate fertilizer 750 g/plant, potash fertilizer 25 g/plant and soil improvement biological bacterial fertilizer 150 g/plant had a more uniform distribution of species and a higher diversity of fungi in the deep soil, and were suitable for improving the diversity of forest deep soil fungal community. Urease had a great influence on the community composition of soil bacteria and fungi, and can be an important soil environmental factor in Poplar forest land.

Key words: Poplar, fertilizer, microbial community structure, soil environmental factors, RDA analysis