SOIL PROPERTIES IN DIFFERENT YEARS OF CULTIVATION ABANDONMENT IN THE MIDSTREAM AND DOWNSTREAM OF SHIYANG RIVER AREA

Abstract

To understand changes of soil properties in different years of cultivation abandonment in the midstream and downstream of Shiyang River area, soil physicochemical characteristics, microbial population, soil microbial biomass, relationships between them and comprehensive evaluation of soil fertility quality were analyzed. The results showed that soil pH increased slightly, soil water content, sand content, the number of bacteria ,the number of actinomycetes and SMBN (soil microbial biomass nitrogen) decreased then increased, soil organic carbon, total potassium, Quick-available K, Quick-available P, SMBC (soil microbial biomass carbon), SMBP (soil microbial biomass phosphorus) and SMBC/SMBN increased then decreased, total nitrogen increased then decreased and tended to be stable, total phosphorus and the number of fungi decreased then increased and decreased finally, and different abandoned years had different significant difference. From the correlation analysis and principal component analysis (PCA), there were close correlations among the soil physical characteristics, soil chemical characteristics and the number of soil microbes, soil microbial biomass. The key factors determining the soil quality were the soil pH, sand content, soil water content, soil water content, total nitrogen, Quick-available K, the number of fungi, SMBC and SMBN. The results that the effects of 4a on the soil during restoration were better for soil improvement than the other abandoned years, making the abandoned years of 4a more critical for use in the ecological restoration and control of the midstream and downstream of Shiyang River area.