A Comparative Study on Soil Properties and Enzyme Activities Between Picea schrenkiana Forestlands and Grasslands at Different Altitudes

This study focuses on Picea schrenkiana forests and surrounding grasslands in the middle reaches of the Toutun River Basin in Changji City, Xinjiang. It analyzes the distribution patterns and correlations of soil physicochemical properties and enzyme activities along an altitudinal gradient. Field sampling and laboratory analysis were employed to measure soil bulk density, water content, porosity, total nitrogen, total phosphorus, total potassium, organic matter, and the activities of urease, acid phosphatase, sucrase, and catalase. The results indicate that forest soils generally exhibited higher porosity, total nitrogen, organic matter content, and acid phosphatase, sucrase, and catalase activities compared to grassland soils. In contrast, grassland soils showed higher bulk density, water content, total phosphorus, total potassium content, and urease activity. Soil enzyme activities were positively correlated with soil organic matter, water content, and porosity, but negatively correlated with total potassium and bulk density. Grassland soil enzyme activities were primarily driven by soil nutrients, whereas forest soil enzyme activities were co-regulated by physical structure and organic matter. The vegetation type is a key factor mediating the response of soil enzyme activities to altitudinal gradients.