土壤物理结皮裂缝发育规律  

Mechanisms of Soil Physical Crust Crack Formation

作　　者：王泽 封瑞坤 王健[1] 师小丹 雷齐娜 WANG Ze;FENG Ruikun;WANG Jian;SHI Xiaodan;LEI Qina(Institute of Soil and Water Conservation,Northwest A&F University,Yangling,Shaanxi 712100,China;Hancheng District Soil and Water Conservation Workstation,Hancheng,Shaanxi 714000,China)

机构地区：[1]西北农林科技大学水土保持研究所,陕西杨凌712100 [2]韩城市水土保持工作站,陕西韩城714000

出　　处：《水土保持学报》2025年第1期208-216,共9页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(42377332)。

摘　　要：[目的]土壤物理结皮是裸露地表常见的一种障碍现象,伴随土壤干燥化将形成干缩裂缝,直接影响土壤水分的蓄存与利用。为明确土壤物理结皮裂缝的发育规律。[方法]通过人工模拟降雨模拟不同类型物理结皮形成,在干燥过程中形成裂缝,采用石蜡填充方法,对裂缝面积、周长、长度和宽度等参数进行测定,定量分析不同条件下沉积结皮和结构结皮裂缝的几何特征和空间变化。[结果]沉积结皮裂缝(DC)在裂缝几何参数方面显著高于结构结皮裂缝(SC)。随着降雨历时增加,裂缝形状系数和密度呈下降趋势,而裂缝平均宽度增加。试验发现3种结皮裂缝的横向收缩类型,分别为贯穿式(PS)、镶嵌式(IS)和悬浮式(SS)。随着降雨历时增大,PS占比逐渐增大,IS、SS占比逐渐减小。随着土层深度增加,沉积结皮裂缝在不同降雨历时表现出阶梯式下降和短暂增加的现象,而结构结皮裂缝则表现为先剧烈后平缓下降趋势。[结论]结皮类型及结皮降雨历时对裂缝发育具有重要影响。考虑到结皮因素对裂缝发育的影响,及时进行田间管理,改变降水的入渗与水分蒸发,为田间管理提供技术支持。[Objective]Soil physical crusting is a common obstructive phenomenon on exposed surfaces,it can lead to shrinkage cracks as the soil dries,thus directly affecting soil moisture retention and utilization.This study aimed to clarify the development patterns of cracks in physical crusts.[Methods]Artificial rainfall was employed to simulate the formation of different types of physical crusts,followed by crack formation during the drying process.Parameters such as crack area,perimeter,length,and width were measured using a paraffin filling method,the geometric characteristics and spatial variations of cracks in depositional crusts(DC)and structural crusts(SC)under different conditions were quantitatively analyzed.[Results]Cracks in depositional crusts(DC)exhibited significantly higher geometric parameters compared to those in structural crusts(SC).With increasing rainfall duration,the crack shape coefficient and density decreased,while the average crack width increased.Three types of lateral shrinkage cracks were identified,including penetrating shrinkage(PS),interlocking shrinkage(IS),and suspended shrinkage(SS).As rainfall duration increased,the proportion of PS increased,while IS and SS proportions decreased.As soil depth increased,cracks in depositional crusts displayed a stepped decrease and a brief increase under different rainfall durations,while cracks in structural crusts showed an initial sharp decrease followed by a gradual decline.[Conclusion]The type of crust and rainfall duration are crucial factors influencing crack development.This study highlights the impact of crusting on crack formation,suggesting timely field management practices to modify water infiltration and evaporation,and can provide a technical support for effective field management.

关 键 词：结皮 干缩裂缝 降雨历时 裂缝几何形态 

分 类 号：S152.7[农业科学—土壤学]