典型岩溶石山山坡土壤剖面水分分层性特征及其影响因素
Stratification of soil profile moisture and its influence factors in typical karst stone hillslope
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摘要: 目的揭示岩溶石山山坡土壤剖面水分的分层性及其与土壤理化性质间的相互关系,为我国南方岩溶地区石漠化治理、水土流失和岩溶水文过程等研究提供科学依据.方法选取典型岩溶石山山坡土壤剖面进行分层取样,结合统计分析方法,研究岩溶石山地区土壤水含量的垂向分布特征及其影响因素,分析土壤剖面水含量的分层特征.结果岩溶石山山坡土壤剖面水含量具有明显差异,变化范围为34.66%~47.10%,平均值为38.15%,土壤质量水含量的最大值出现在35 cm深处.相关性分析结果表明,土壤质量水含量与有机质含量呈显著正相关(P<0.05,下同),与pH呈显著负相关,与中值粒径相关性不显著(P>0.05);有机质通过改善土壤团聚体结构影响土壤质量水含量变化.土壤质量水含量及理化性质的变化具有分层性,地表至35 cm为表土层,35~85 cm为过渡层,85~115 cm为稳定层.结论岩溶石山地区土壤剖面水分具有明显的分层性,是土壤性质、结构特征、根系活动、水分运动、化学淋滤作用及基岩界面综合作用的结果,尤其应注意20~40 cm处植被根系活动及基岩界面对土壤剖面水分变化的影响.Abstract: ObjectiveStratification of soil profile moisture and the relationship between soil profile moisture and soil physicochemical properties of karst stone hillslope were studied with the purpose of providing a scientific basis for rocky de-sertification treatment, water and soil erosion and karst hydrological processes in karst areas of southern China. MethodTypical karst stone hillslope soil profile was used as sample. Stratified sampling integrated with statistical analysis method was applied to study vertical distribution characteristics and its influencing factors,and to analyze stratification of soil profile moisture. ResultThere was obvious difference in soil profile moisture content of karst stone hillslope. It ranged from 34.66% to 47.10%,with the mean value of 38.15%. The maximum value of soil mass moisture was at the depth of 35 cm. Co-rrelation analysis results showed a significant positive correlation between soil mass moisture content and organic matter content(P<0.05, the same below). There was significant negative correlation between soil mass moisture content and pH. The correlation between it and median diameter was insignificant(P>0.05). Organic matter affected soil moisture content through improving soil aggregate structure. The variations of soil mass moisture content and soil physicochemical properties exhibited a distinctive stratification which could be divided into topsoil layer(from surface to the depth of 35 cm),transition layer(depth 35-85 cm) and stable layer(depth 85-115 cm). ConclusionSoil profile moisture in karst stone area has obvious stratification, which is a combined results of soil property,structure characteristics,root activities,water movement,chemi-cal eluviation and bedrock interface. In particular, effects of root activities in depth of 20-40 cm and bedrock interface on soil profile moisture should be paid more attention to.