黔中石漠化地区不同土地利用方式对土壤环境的影响

在贵州省普定县喀斯特石漠化地区通过调查分析，对3种土地不同利用方式（Ⅰ封山育林地、Ⅱ退耕还林地、Ⅲ农耕地）土壤物理性质、化学性质及土壤种子库进行了研究。结果表明利用方式的不同对土壤物理性质、化学性质及土壤种子库均产生了显著的影响。土壤容重、土壤毛管孔隙度随土壤扰动的加剧而下降，表现为Ⅰ＞Ⅱ＞Ⅲ；土壤总孔隙度与非毛管孔隙度呈现出随土壤扰动程度增加而增加的趋势，表现为Ⅲ＞Ⅱ＞Ⅰ；不同层次之间容重的变异较小，土壤质地比较均一；Ⅱ土壤有机质低于类型Ⅲ和Ⅰ；Ⅰ初步形成了林地环境，林地土壤表现出良性转变。随土壤深度的增加，有机质、全氮、全磷、速效氮表现出减少的趋势，土壤扰动降低了土壤化学性质层次间变异。不同利用方式下土壤种子库物种组成变化不大，土壤中的种子集中分布在表层0～5 cm内，随土层的加深所含种子数量、物种数逐渐降低。不同利用类型的土壤种子数量在0～5 cm层次差异显著（〖WTBX〗p〖WTBZ〗=0.021 897），种子种类差异不显著（〖WTBX〗p〖WTBZ〗=0.097 628）。土壤扰动促进种子向深层传播，退耕还林有利于土壤质量的恢复。

EFFECT OF DIFFERENT LAND USE MODES ON SOIL ENVIRONMENT IN KARST ROCKY DESERTIFICATION ZONE, MIDDLE GUIZHOU PROVINCE OF CHINA

By investigating the soil physical and chemical properties and soil banks of three different applied soils (Ⅰ closing hill for regeneration,Ⅱ retired farmland for forest land,Ⅲ farmland) in karst rock desertification zone in Puding City of Guizhou Province of China,it was found that soil physical and chemical properties,soil banks of different applied soils were distinctly different.Soil bulk density and capillary porosity dropped with the increase of disturbance(Ⅰ＞Ⅱ＞Ⅲ).The total soil porosity and non capillary porosity increased with disturbance(Ⅲ＞Ⅱ＞Ⅰ).The changes of soil bulk density were slight,the soil textures were similar in each type.The organic matter content of Ⅱ was lower compared to Ⅲ andⅠ.The change of type Ⅰ was due to the formation of forest environment.Organic matter content,total N, total P,dissoluble N dropped with the increase of soil depth.The disturbance reduced the change of soil chemical properties.There are slight differences in soil bank species under different land use modes and quantities of seeds,species decreased with the increase of depth.Seeds mostly lay in 0～5 cm soil,and the difference of seed number was significant (〖WTBX〗p〖WTBZ〗=0.021 897),whereas the difference of species was not (〖WTBX〗p〖WTBZ〗=0097 628).Disturbance of soil could accelerate the distribution of seeds to deeper soils,and retired farmland for forest land would benefit soil quality recovery.〖