赤水河上游主要树种根际土壤调控水分功能研究

为明确赤水河上游主要树种根际土壤调控水分能力，通过野外采样和室内分析方法，从容重、含水率和孔隙度等方面入手研究水文生态功能，并划分调控水分功能群。结果表明:32个树种0—60 cm的最大持水量为212.00～357.94 mm、有效贮水量为11.07～85.15 mm，是一个蓄水库；其持水速率大于失水速率，且二者与时间的关系均符合幂函数模型。采用RDA排序时，可将该区的树种划分为5类功能群:功能群Ⅰ包括杨梅、丝栗栲、茶、白栎、马尾松、慈竹；功能群Ⅱ包括杨树、杉木、构树、荚蒾、撑绿竹、枫香、火棘、山胡椒、乌桕、楝树、马桑；功能群Ⅲ包括枇杷、南天竹、李、柏木、梧桐、香椿；功能群Ⅳ包括檵木、黄荆、油桐、毛桐、南酸枣；功能群Ⅴ包括盐肤木、黄连木、柑橘、油茶。土壤容重、含水率、孔隙度等物理特征和持水过程是影响土壤水分调控能力的主因。研究结果可为赤水河上游水源涵养林树种的选择和配置提供理论依据。

Soil Water Regulation Function in the Rhizosphere of Main Tree Species in the Upper Reaches of Chishui River

In order to understand the soil water regulation ability in rhizosphere of main tree species in the upper reaches of Chishui River, through field sampling and experimental analysis method, study on ecohydrological function was carried out based on the bulk density, water content, porosity and other aspects, and the division of water regulation function groups. The results showed that the maximum water holding capacity of 32 species in 0—60 cm layer is about 212.00~357.94 mm, available water content ranged from 11.07 mm to 85.15 mm, was the reservoir; water holding rate was greater than the rate of water loss, and the relationship between the two and the time followed the power function model. Using RDA ordination, tree species in this area could be divided into 5 types of functional group. Functional group Ⅰincluded Myricaceae rubra, Castanopsis fargesii, Camellia sinensis, Quercus aliena, Pinus massoniana and Neosino calamus affinis. Functional group Ⅱ included Populus trinervis, Cunninghamia lanceolata, Broussonetia papyifera, Viburnum chinshanense, Bambusa pervariabilis, Liquidamba formosana, Pyracantha fortuneana, Lindera glauca, Sapium sebiferum, Melia azedarach and Coriaria nepalensis. Functional group Ⅲ included Eriobotrya bengalensis, Nandina domestica, Prunus nalicina, Cupressus funebris, Platanus acerifolia and Toona sinensis. Functional group Ⅳ included Loropetalum chinense, Vitex negundo, Vernicia fordii, Mallotus barbatus and Choerospondias axillaria. Functional group Ⅴ included Rhus chinensis, Pistacia chinensis, Citrus reticulata and Camellia oleifera. Physical characteristics like soil bulk density, water content and porosity and water holding process are the key factors which affect the ability of regulation of soil hydrology. The results can provide theoretical basis for the selection and configuration of tree species in the water conservation forest of upper Chishui River.