| 三峡库区碎石含量对紫色土容重和孔隙特征的影响 |
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| 引用本文： | 王小燕,蔡崇法,李 鸿,谢德体.三峡库区碎石含量对紫色土容重和孔隙特征的影响[J].土壤学报,2017,54(2):379-386. |
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| 作者姓名： | 王小燕 蔡崇法 李 鸿 谢德体 |
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| 作者单位： | 1. 西南大学资源环境学院三峡库区生态环境教育部重点实验室,重庆,400715;2. 华中农业大学资源与环境学院水土保持研究中心,武汉,430070 |
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| 基金项目： | ?国家自然科学基金项目（41401298）、中央高校基本科研业务费专项（XDJK2013C152）与高等学校博士学科点专项科研基金新教师类课题（20130182120015） |
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| 摘 要： | 土壤容重和孔隙分布特征是土壤重要的基本物理性质,但有关含碎石土壤的物理性质以及碎石含量对土壤结构影响的研究尚不多见。三峡库区紫色土中存在大量的碎石,为了深刻了解和评价土壤中碎石对容重与大孔隙形成的可能作用,通过野外调查、典型土样采集和室内分析实验,探讨了三峡库区典型土地利用类型下土壤中的碎石体积含量以及不同粒径碎石的基本物理性质及其对土壤容重和孔隙特征的影响。结果表明:土壤中碎石的孔隙度和饱和含水率随着碎石粒径的减小而增大,小碎石本身具有一定的持水、供水性能;碎石含量对土壤的总容重、细土容重有显著影响,随着碎石含量的增加,土壤的总容重逐渐增加,而细土容重与碎石含量呈线性负相关关系,土壤中碎石的存在有利于改善土壤的结构;土壤孔隙分布特征与碎石含量密切相关,随着碎石含量的提高,土壤总孔隙度和毛管孔隙度呈减少趋势,而非毛管孔隙度即大孔隙呈增加趋势,碎石的存在有利于改善土壤的透水性能。本研究为山区农用地灌溉与水分管理提供了科学依据。
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| 关 键 词： | 紫色土 碎石 容重 孔隙 三峡库区 |
| 收稿时间： | 2015/11/25 0:00:00 |
| 修稿时间： | 2016/10/17 0:00:00 |
Influence of Rock Fragments on Bulk Density and Pore Characteristics of Purple Soil in Three-Gorge Reservoir Area |
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| WANG Xiaoyan,CAI Chongf,LI Hong and XIE Deti.Influence of Rock Fragments on Bulk Density and Pore Characteristics of Purple Soil in Three-Gorge Reservoir Area[J].Acta Pedologica Sinica,2017,54(2):379-386. |
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| Authors: | WANG Xiaoyan CAI Chongf LI Hong and XIE Deti |
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| Affiliation: | Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Resources and Environment, Southwest University,Soil and Water Conservation Center, College of Resources and Environment, Huazhong Agricultural University,Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Resources and Environment, Southwest University and Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Resources and Environment, Southwest University |
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| Abstract: | Objective] Bulk density and pore distribution characteristics are two fundamental soil properties.However,not much has been reported about physical properties of soils containing rock fragments and influences of rock fragments in soil on bulk density and formation of non-capillary porosity of the soil.Purple soil is the major type of soil in the Three-Gorge Reservoir Region and the high content of rock fragments is one of the important characteristics of the purple soil.The existence of plentiful rock fragments in the soil will sure affect the formation of bulk density and porosity characteristics.The purpose of this study is to understand how rock fragments affect bulk density and porosity characteristics and its possible mechanism in the purple soil of the region.It is expected that the findings in this study may help collect some basic parameters of soil spatial distribution for building models to be used to predict spatio-temporal variation of surface runoff and soil erosion,while providing some scientific bases for irrigation and water management of agricultural land in mountainous areas.Method] In order to explore in depth and evaluate potential effects of rock fragments on bulk density and porosity characteristics,soil samples typical of the soil were collected during field surveys for in-lab analysis of contents and fractions of rock fragments in particle size,soil physical properties,bulk density and porosity.Result] (1) Rock fragments varied sharply in density,porosity,saturated water content,and weathering degree.The larger in size,the lower in weathering degree,the higher in density,and the lower in porosity and saturated water content.The three fractions of rock fragments,small,medium and large,were 1.9,2.2 and 2.3 g cm-3 in density,0.16,0.10 and 0.06 cm3 cm-3 in porosity and 8.0％,4.5％ and 3.2％ in saturated water content (mass moisture content),respectively.(2) Content of rock fragments was closely related to total bulk density and bulk density of fine earth.With increasing rock fragment content,total bulk density increased while bulk density of fine earth decreased,showing a linear negative relationship.(3) Soil pore distribution was closely related to content of rock fragments.With increasing content of rock fragments,total porosity and capillary porosity of the soil decreased while non-capillary porosity,i.e.macrospore,increased.Conclusion] The sum up,rock fragments,especially those small in size,have certain water holding and supplying capacities.In farmlands under water stress,rock fragments can also release some water available for plant growth.The existence of rock fragments in the soil helps improve soil structure and soil water permeability. |
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| Keywords: | Purple soil Rock fragment Bulk density Porosity Three-Gorge Reservoir Area |
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