岷江上游中山区低效林改造对土壤物理性质的影响

岷江上游中山区存在大面积低效林,其萌蘖枝多而密,无明显主干,林地阴闭,光照少,土壤干燥,生态服务功能极为低下。经萌蘖更新调控技术2 a的改造后,土壤生态功能大大改善,改造林地土壤容重较对照林地低9.6%~32.6%,土壤孔隙状况明显改善,表层总孔隙和毛管孔隙较对照林地提高30.9%和31.5%,非毛管孔隙随改造时间先增加后减少,土壤孔隙配比更为合理。由于土壤孔隙得到改善,土壤持水性能也明显地提高,表层最大持水量、毛管持水量及自然含水量较对照林地分别提高87.5%,94.6%和64.0%,非毛管持水量在改造2 a后,表层土壤也较对照林地高72.3%。萌蘖更新调控技术通过调控植物结构和功能,加快林地物质循环,促进植物生长和根系活动能力,来改善土壤生态功能。萌蘖更新技术在岷江上游中山区试验效果明显,土壤蓄水保水能力强,为该技术推广应用提供了一定的理论基础。

Effect of Low-quality and Benefit Forest Improvement on Soil Physical Properties in Middle-mountain of Upper Reaches of Minjiang River

There is a large area of low-quality and benefit forest in middle-mountain of the upper reaches of Minjiang river. High density root-sprouts which are not obvious stem formed shaded condition where there are low light and dry soil of forests. These low-benefit and quality forests are improved by root-sprout regeneration technique for 2 years. Soil ecological functions are ameliorated significantly. Soil bulk density of improved woodland decreased 9.6 %-32.6 % than that of control, soil total porosity of improved woodland was also significantly ameliorated, soil total porosity and capillary porosity of topsoil in improved woodland increased 30.9% and 31.5% than that of control, respectively. Ratio of capillary porosity and non-capillary porosity became even more rational. As a result of melioration of soil porosity condition, the capacity of water-holding was also ameliorated. The maxi- mal, capillary capacity of water-holding and natural moisture content in improved woodland increased 87.5%, 94.6% and 64.0% than that of control, respectively. The non-capillary capacity of water-holding also increased 72.3% after 2 years. Root-sprout regeneration technique accelerated material circulation, root activity and plant growth and ameliorated soil ecological function through the control of plant structure and function. Root-sprout regeneration technique that increased the capacity of water-holding is a good technique, and it should be popularized in middle-mountain of the upper reaches of Minjiang river.