喀斯特槽谷区岩层倾向对土壤入渗特性的影响

为了解岩层倾向对喀斯特槽谷区土壤入渗特性的影响,以重庆市青木关岩溶槽谷区顺/逆层坡为研究对象,分析5种典型土地利用方式裸地(AL)、辣椒地(PL)、玉米地(CL)、林地(FL)、草地(GL)在顺/逆层坡的土壤入渗能力差异,并探讨土壤物理性质对土壤入渗能力的影响。结果表明:(1)＞0.25 mm水稳性团聚体含量、毛管持水量、黏粒以及粉粒含量在顺/逆层坡存在显著差异(p<0.05),其中在>0.25 mm水稳性团聚体含量和毛管持水量方面,分别为PL与FL的顺/逆层坡差异最大,在黏粒和粉粒方面,CL的顺/逆层坡差异最大,且均为逆层坡＞顺层坡。(2)除FL顺层坡的土壤渗透能力低于逆层坡外,其余4种土地利用方式下的土壤入渗能力均表现为顺层坡高于逆层坡。(3)土壤渗透特性在顺/逆层坡均与容重呈极显著负相关关系(p<0.01),在顺层坡与总孔隙度、非毛管孔隙度、＞5 mm水稳性团聚体含量和饱和持水量呈极显著正相关关系(p<0.01),在逆层坡与非毛管孔隙度、饱和持水量、粉粒含量呈极显著正相关关系(p<0.01);通过多元逐步回归分析与通径分析发现,顺/逆层坡土壤入渗能力的首要决策因素均为容重,其次分别为>5 mm水稳性团聚体含量和粉粒含量。(4)对比4种土壤入渗过程的拟合模型,Philip模型对顺/逆层坡的土壤入渗过程拟合效果最佳。研究结果可为喀斯特槽谷区不同岩层倾向的水土流失防治以及植被恢复提供数据支撑。

Effects of Rock Strata Dip on Soil Infiltration Characteristics in Karst Trough Valley Area

In order to understand the impact of rock strata dip on soil infiltration characteristics in karst trough valley area, taking the dip/anti-dip slope of Qingmuguan karst trough valley area in Chongqing as the research object, the differences of soil infiltration capacity of five typical land use patterns, namely abandoned land (AL), pepper land (PL), corn land (CL), forest land (FL), grassland (GL) in dip/anti-dip slope were analyzed, and the influence of soil physical properties on soil infiltration capacity was discussed. The results showed that: (1) There were significant differences in >0.25 mm water-stable aggregate content, capillary water holding capacity, clay and silt content between the dip and anti-dip slope (p<0.05). In terms of >0.25 mm water-stable aggregate content and capillary water holding capacity, the greatest differences were found between the dip and anti-dip slope of PL and FL, respectively, and in terms of clay and silt content, the greatest differences were found between the dip and anti-dip slope of CL, and both were anti-dip slope > dip slope. (2) Except for the soil infiltration capacity of FL, the soil infiltration capacity of the dip slope was lower than that of the anti-dip slope, and the soil infiltration capacity of the other four land use patterns was higher than that of the anti-dip slope. (3) Soil infiltration characteristics showed highly significant negative correlation with bulk density on dip and anti-dip slope (p<0.01), and had significantly positive correlation with total porosity, non-capillary porosity, >5 mm water-stable aggregate content and saturated water holding capacity in the dip slope (p<0.01), and had significantly positive correlation with non-capillary porosity, saturated water holding capacity and silt content in the anti-dip slope (p<0.01). The multiple stepwise regression analysis and path analysis revealed that the primary decision factor for the soil infiltration capacity on dip and anti-dip slope was both the bulk density, followed by >5 mm water-stable aggregate content and silt content, respectively. (4) Compared with the four fitting models of soil infiltration process, Philip model had the best fitting effect on the soil infiltration process of the dip and anti-dip slope. The research results can provide data support for soil erosion control and vegetation restoration in different rock strata dips in karst trough valley area.