1.土壤退化及其分类 土壤退化 土壤(地)退化是由自然因素和人为因素共同作用的结果,破坏性自 然灾害以及异常的成土因素是引起土壤自然退化(侵蚀、砂化、盐化 和酸化等)的基础,而人类的不合理利用则是加剧土壤(地)退化的 根本原因

一、分布 有一定种稻历史的地区就有水稻土的分 布。我国水稻土大约占全国耕地面积的 1/5,主要分布在秦岭、淮河以南地区。 我省水稻土占全省耕地总面积的83%, 是我省最重要的粮食和经济作物的生产 基地

Determination of the relative movement of the two walls from the tension joints

TERMINOLOGY FOR DISPLACEMENT a is the rake angle

Main Bedding Types Bedding Shape level bedding ripple bedding Main Types of plate laminae

CONSTRUCTION OF VERTICAL SECTION 1 Select the location of the section and draw a section line (usually perpendicular to the strike of the main structures), right-hand end is its more easterly end 2 Draw a topographic profile along the line of section. Determine the base line on the squared

Review Show the homework and note book on your desk Practise measurement of attitude of planes and lines in the models

Determination of the top sur faces of the beds from the scour surfaces

Chapter 2 Primary Sedimentary Structures Main types of bedding Determination of younger direction of beds from primary structures Types of stratigraphic break Angular unconformity Soft sedimentary structures

Chapter One Introduction Goals Outline Two supports Types of structures QA uantitative techniques pplication Suggestion