东北黑土区黑土层厚度的时空变化

黑土层厚度是评价东北黑土区土壤质量的重要参数，但其厚度的空间分布及多年变化情况仍然不够明确.针对东北黑土区第二次土壤普查的61处典型土壤剖面进行了现状实地调查，并对黑土层厚度变化进行了对比分析.结果表明:近40年来，东北黑土区黑土层厚度平均减少了12cm，平均减薄速度为0.32cm/a.四省(区)黑土层减薄厚度具有显著差异，表现为吉林(23.65cm)>辽宁(11.83cm)>内蒙古(10.33cm)>黑龙江(6.83cm).吉林省黑土层减薄厚度和比例最大，生态风险最为严峻.吉林省黑土层厚度变化值与气温升高值呈显著的负相关关系，表明随着气候变暖，土壤有机质下降明显，黑土层的厚度也呈减薄趋势.研究表明，水蚀作用也是黑土层厚度减薄的重要影响因素.未来应加强黑土层厚度判定和黑土层厚度空间制图等方面研究，对指导黑土地保护利用具有重要意义.

SPATIOTEMPORAL VARIATION OF BLACK SOIL LAYER THICKNESS IN BLACK SOIL REGION OF NORTHEAST CHINA

The thickness of black soil layer is an important parameter to evaluate the soil quality in Northeast China. To find out its spatial distribution and secular variation, the paper conducts field investigation on the present condition of 61 typical soil profiles from the Second National Soil Survey in the black soil region of Northeast China and analyzes the variation of black soil layer thickness. The results show that the thickness of black soil layer has decreased by 12 cm on average, with the mean thinning rate of 0.32 cm/a in the past 40 years. The thinning thickness of black soil layer in four provinces/regions are significantly different, with the largest thickness and proportion of black soil layer thinning and the most severe ecological risk in Jilin(23.65 cm), followed by Liaoning(11.83 cm), Inner Mongolia(10.33 cm) and Heilongjiang(6.83 cm). There is a remarkable negative correlation between the black soil layer thickness variation and rising temperature in Jilin Province, indicating that with the climate warming, soil organic matter decreases obviously, and also the thickness of black soil layer. In addition, water erosion is also an important factor affecting the thickness thinning of black soil layer. It is suggested the study on black soil thickness determination and spatial mapping be strengthened in the future, which is of great significance to guide the protection and utilization of black land.