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在贵州中部典型喀斯特石漠化区选择2个试验样地进行树轮地貌学研究,通过对样地内计22对裸露和非裸露树根进行野外测定并取样进行室内测试,表明:喀斯特裸露根系记录了土壤侵蚀结果,裸露树根解剖结构显示土壤侵蚀发生时树根细胞生长发生明显变化,显示出年轮突然变窄、细胞明显减小、或者早材细胞数量减少等,同时,纤维面积、导管管胞面积也发生显著下降,多达70.66%,少则39.20%,而这种变化仅只与土壤侵蚀有关,结合树根年龄测定,得到土壤侵蚀发生的准确时间,并据此计算出样地尺度土壤侵蚀的动态过程,其中普定土壤侵蚀量发生在2002-2007年之间,平均侵蚀速率为每年0.484 t;贞丰土壤侵蚀发生在2005-2007年之间,平均侵蚀速率为每年0.051 t。树轮记录的土壤侵蚀不仅可以同一个物种进行测定,还可以多物种共同记录,这为以多物种阔叶混交林为主要植被的喀斯特土壤侵蚀记录的研究提供了强有力的方法;而树轮记录的土壤侵蚀量大大大于径流场监测的流失量,显示喀斯特地下流失为主,流失量占总土壤侵蚀量的2/3。
In the typical karst rocky desertification area in central Guizhou, two test sites were selected to study the tree-ring geomorphology. Through field measurements of 22 exposed and non-exposed roots of the plot in the plot and laboratory sampling, it was shown that the karst root system records Soil erosion results showed that the anatomical structure of bare roots showed that the root growth significantly changed when soil erosion occurred, which indicated that the ring suddenly narrowed, the number of cells decreased or the number of early wood decreased. At the same time, the fiber area, The tracheid area also decreased significantly, up to 70.66%, while the difference was only 39.20%. However, this change was only related to soil erosion. Combined with the determination of root age, the exact time of soil erosion was obtained, and the sample size The dynamic process of soil erosion, in which Puding soil erosion occurred between 2002-2007, the average erosion rate of 0.484 t per year; Zhenfeng soil erosion occurred between 2005-2007, the average erosion rate of 0.051 t per year. Soil erosion recorded by tree-ring can not only be measured by the same species, but also recorded by multiple species. This provides a powerful method for the study of karst soil erosion records with multi-species broad-leaved forest as the main vegetation. The recorded amount of soil erosion is much larger than that of the runoff field monitoring, indicating that underground karst is the dominant type of karst, accounting for two-thirds of total soil erosion.