高原喀斯特土壤养分容量及其林木持续性研究

以高原喀斯特地区土壤为研究对象,研究了土壤中理化指标,探讨了该地区植物生长动态和土壤中营养元素丰缺现状,并对植物生长的土壤养分容量库进行了估算。结果表明:喀斯特高原土壤土层较浅,土壤中钾素丰富,氮素、磷素含量较低,氮素是林木生长的主要限制因子;相比之下,磷素在林地土壤中总量低于钾素与氮素,但其有效态所占的比例高于氮和钾,可能是林木生长过程对磷的吸收利用率高于氮和钾。在次生林生态系统群落结构没有大的变化调整条件下,该地区0.1公顷土壤至少能提供云南鼠刺、圆果化香、槲栎等136棵乔木理想状态下生长发育近600年的养分。土壤有效态养分含量可以满足植物生长的养分需求,但在100年后植物体生长发育主要受到有效磷素的限制。

Soil Nutrient Capacity and Forest Tree Sustainability in Plateau Karst Region

The present study addresses on soil contents in karst plateau region. Physicochemical indexes of soils were tested, and plant growth dynamics and the present status of nutrients in soils were discussed. In addition, the nutrient capacity of soils, in which plant growing, was estimated as well. Results suggest that soil thickness of karst plateau was shallow, and soil potassium was abundant. Soil nitrogen and phosphorus were low, and nitrogen was the limiting factor for plants growth. The total concentration of soil phosphorus was lower than those of soil potassium and nitrogen. On the contrary, the available fraction of phosphorus took a greater percentage of the total phosphorus than those of potassium and nitrogen. This probably indicates that plants in study region have a high use efficiency on phosphorus than those on potassium and nitrogen. If no significant change took place on the plant community structure, a hectare land could support 136 trees(including Itea yunnanensis, Platycarya longipes and Quercus aliena) survival 600 years in ideal status. According to present research, available contents of studied nutrients in soils were adequate to meet the needs of plants growth. However, plants growth in study region will, probably, be limited by available phosphorus.