人工桉林土壤孔隙状况及水分变化分析

摘要

Objective] This study almed to investigate the characteristics of soiI total porosity (STP) and various factors affecting soiI water content (SWC) in eucalyptus pIantation (EP), thereby providing references for soiI water utiIization in eucalyptus pIanting in the red soiI hiI y region of South China. [Method] In the same cIimatic region, soiI sampIes were coI ected from surface soiI Iayer (A), iI uvial horizon (B) and parent material horizon (C) in the upper sIope, middIe sIope and Iower sIope of eucalyptus pIantation, native forest and pine forest, respectiveIy, to determine the soiI porosity and soiI water content and analyze changes and various infIuencing factors of soiI water content in horizontal and vertical direction. [Result] Average soiI porosity in eucalyptus pIantation, native forest and pine forest was 45.9%, 41.4%and 55.3%, respectiveIy; soiI water content in these three forest stands was 13.3%, 13.4% and 15.5%, respectiveIy. In addition, soiI water content in these three forest stands exhibited no significant differences (P>0.05) among different soiI profiIes and sIope positions, but soiI water content in surface soiI Iayer varied significantIy (P<0.05) among different forest stands; in the horizontal direction, soiI water content exerted an extremeIy significant positive correIation with total coverage. [Conclusion] Total coverage of canopy Iayer, herb and Iitter Iayer is one of the most critical fac-tors affecting the changes of soiI water content in surface soiI Iayer of forest stands.%[目的]探明人工桉林的土壤孔隙状况及水分含量变化影响因子，为华南红壤丘陵区桉树种植生产中土壤水分利用提供参考依据。[方法]在相同气候区内，按上中下不同坡位，采集表土层（ A）、淀积层（ B）和母质层（ C）3个不同剖面发生层的土壤，测定人工桉林、天然林、松林的土壤孔隙度和水分，并在垂直和水平方向分析土壤水分含量的差异状况及影响因子。[结果]A、B、C 3层的人工桉林、天然林与松林的土壤孔隙度平均值分别为45.9%和41.4%、55.3%，水分平均值分别为13.3%、13.4%和15.5%，这3种林分的土壤水分在剖面上和坡位上不存在显著差异（P＞0.05），但不同林分间的表层土壤水分存在显著差异（P＜0.05）；在水平方向上，总盖度与土壤水分存在极显著正相关。[结论]冠层及草本、落叶层的总盖度是林分表层土壤水分变化的主控因素之一。