中南地区典型地带性土壤的斥水性及其影响因素分析

Soil Repellency and the Factors that Affect It in Typical Soils in Central-southern China

选取我国中南地区不同发育程度典型旱作土壤为研究对象,通过测定土壤基本理化性质与滴水穿透时间(WDPT),探究了该区域土壤斥水性变化规律及其影响因素。结果表明,(1)自北向南,随着水热条件增加,土壤p H值逐渐降低,游离氧化物(Fed、Ald)逐渐增加,非晶质氧化物(Feo、Alo)没有明显的地带性变化;表层有机质量高于下层,而林地表层高于耕地表层;(2)供试土壤均为亲水性土壤,WDPT分布在0.47~4.00 s之间,自北向南土壤斥水性整体呈逐渐降低的趋势;(3)WDPT与p H值、CEC、粉粒量显著正相关(r>0.54,p<0.05),砂粒量、非晶质氧化铁(Feo)、游离氧化铁、铝(Fed、Ald)与WDPT呈负相关关系(r<-0.56,p<0.05)。逐步回归分析表明,Fed和Feo对土壤斥水性的影响最显著(R2=0.71,p<0.01),可以用来评价和预测土壤斥水性。

This paper measured the repellency （SWR） of typical soils under different weathering conditions in central-south China using the water drop penetration time （WDPT） method. We also examined the spatial variation of SWR and its dependence on soil physicochemical properties. The main results are： ①With the increase in moisture and temperature from the center to the south, soil pH gradually decreased while the free iron （Fed） and aluminum （Ald） oxides increased. The amorphous iron （Feo） and aluminum （Alo） oxides did not show noticeable change over space as the free oxides did. Soil organic matter was higher in top soil than in subsurface soil, and higher in forest soil than in arable soil.② All soils studied were hydrophilic with the WDPT ranging from 0.47 to 4.00 s; the SWR generally decreased from the center to the south （p〈0.05）. ③ WDPT was positivelyrelated to pH, cation exchange capacity, silt content （r〉0.54, p〈0.05）, but negatively related to sand content, Feo, Fed and Ald （r〈-0.56, p〈0.05）. Stepwise regression showed that Fed and Feo affected soil repellency most （R^2=0.71 ,p〈 0.01）. The results in this paper provide reference for improvin- soil water management.