黑土层是黑土形态上最突出的特点,是腐殖质及植物其他营养物质聚集的层次.厚度一般为30—70厘米,厚的可达1米以上,薄的小于20厘米.黑土层是由草甸草原植物残体形成的.具有深厚黑土层的黑土,肥力水平较高,作物产量也较高.吉林黑土地区位于我国黑土带的南部,开垦历史较久,黑土层逐渐变薄.本文拟有关不同厚度黑土层酶活性状况及其与碳氮磷含量的关系,对该地区黑土生化特性及肥力演变趋势作一初步讨论. Black soil is the most prominent feature of black soil morphology, humus and other nutrients is the level of accumulation of plants. Thickness is generally 30-70 cm thick, up to 1 m above the thin, less than 20 cm. Black soil is a meadow Grassland plant debris formed. Black soil with deep black soil layer has higher fertility level and higher crop yield. The black soil region of Jilin Province is located in the southern part of China’s black soil zone with long history of reclamation and thinning of black soil layer. The enzyme activity of black soil layer and its relationship with the content of carbon, nitrogen and phosphorus, the biochemical characteristics of black soil and the evolution trend of fertility in the area were discussed.