关闭图标
log图标

toefl.viplgw.cn

  • 使用手机注册
  • 使用邮箱注册
  • 手机号不能为空!

    验证码不能为空!

    用户名不能为空!

    密码不能为空!

  • 邮箱不能为空!

    验证码不能为空!

    用户名不能为空!

    密码不能为空!

已有账号? 登录到雷哥托福
关闭图标
log图标
  • 使用手机找回密码
  • 使用邮箱找回密码
  • 手机号不能为空!

    验证码不能为空!

    密码不能为空!

  • 邮箱不能为空!

    验证码不能为空!

    密码不能为空!

又想起来了
加入生词本

listen

英['lɪs(ə)n] 美['lɪsn]
vi. 听,倾听;听从,听信
n. 听,倾听

已添加
×

我要举报草莓小菇凉评论

用户头像
草莓小菇凉:说的非常好,十分有道理,棒棒棒!

06-08 15:44:55

请选择举报类型:

举报电话:400 1816 180    举报QQ:2095453331
×
logo图标
分享到雷哥托福

分享成功图标分享成功

邀请名师点评成功,管理员正在安排老师进行点评。

继续做题 返回首页
支付雷豆失败图标 雷豆余额不足 购买雷豆 返回
报告题目错误
请选择错误类型:
请描述一下这个错误:

取消

文章结构

Official 29-L1 .Pedodiversity Plant 点击收藏

标准

  • 高音
  • 静音
  • 句子
    精听
  • 全文
    精听
  • 听写
    模式
  • 点击查看本句

    听写本句 再播一遍 下一句
  • 点击查看全文

    再播一遍本文

    Listen to part of a lecture in a plant ecology class.

    So far we have covered biodiversity in the hard wood forest here in the upper peninsula of Michigan from a number of angles.

    We've looked at everything from how biodiversity relates to species stability, to competition for forests resources and more.

    But now I want to discuss what's called pedodiversity.

    Pedodiversity is basically soil diversity.

    When we analyze pedodiversity within an area, we are measuring how much variability there is in soil properties and how many different types of soil there are in a particular area.

    So we look at soil chemistry.

    For example, how much nitrogen or magnesium there's in the soil in one spot.

    And we compare it with the chemistry of the soil a short distance away.

    Until recently, there hasn't been a whole lot of attention paid to pedodiversity.

    But that's changing rapidly.

    More and more studies are being done in these fields.

    There's a link between biodiversity and pedodiversity, an obvious relationship between soils and flora and fauna, which is why pedodiversity really should be considered in forest management.

    A high degree of soil variability in a small area is common, particularly within forests.

    If you compare soils from a forest with soils that don't come from a forest, the amount of variability will most likely be greater in the forest's soil.

    It generally has more diversity.

    Um... OK. There are three main causes of pedodiversity within old-growth forest here in our region of Michigan.

    One is tree species.

    Different species have different influences on soil formation and soil properties.

    For example, pine trees drop pine needles.

    And those needles add a lot of acid to the soil.

    The organic litter of another tree species might add less acid but more of something else.

    A lot of different types of trees in an area might mean more pedodiversity.

    Another cause? Gaps... created when trees fall.

    You see, where there are gaps, open areas in the forest, the soil there changes.

    Um... for instance, without a tree to absorb radiation from the Sun, to offer shade, the full intensity of that radiation reaches the ground.

    The soil where the tree used to be heats up.

    And without a tree to soak up moisture from the ground, the soil remains wetter than in the surrounding forest.

    With a higher temperature and more moist conditions, the process of organic matter decomposition speeds up.

    In other words, organic matter gets broken down and added into the soil more quickly in these gaps than in the surrounding forest.

    OK. And the third cause: trees being uprooted.

    When a tree is uprooted, it might fall into some other trees on its way down, thus falling only partway over.

    Or it might crash all the way down to the forest floor.

    Either way, if its roots are pulled up from out of the ground as the tree topples over, then there's usually a big hole, a pit left in the ground where the roots used to be.

    And there's still a lot of soil attached to the roots, clinging to the roots.

    As that soil is eventually shed from the roots by rain and wind and the movement of squirrels climbing around, things like that.

    Um... as the soil is shed, it drops down and forms a little hill of dirt, a mound.

    Pits and mounds have significantly different soil properties than other areas in the forest.

    You get a redistribution and mixing of soil as deep roots are ripped up from the ground.

    Rock fragments can be pulled up too, if they've gotten entangled with the roots over the years.

    So rock fragments from the subsoil can end up concentrated on the surface.

    There are forests management implications I want to point out.

    Forests management impacts soil quality.

    And when we better understand pedodiversity, we will be better able to predict the impact of forest management on soil.

    But in general, for positive impact, forest management practices should mimic natural forest processes.

    And the goal should be to promote pedodiversity, and through this, biodiversity in general.

    I have a handout, an article on pedodiversity in a section of forests near here.

    I want you to read it, because it makes a point that I've only touched on.

    From what I have been saying about the causes of pedodiversity, you might assume that the relationship between forest dynamics, what happens to the trees, and pedodiversity is a one-way street.

    As the article explains, forest dynamics affects pedodiversity.

    But pedodiversity also affects forest dynamics.

    It's worth bearing in mind.

    • special
    ☞查看答案 再播一遍

联系雷哥托福

全国免费咨询热线:400 1816 180

  • 上海(总部)
  • 北京
  • 成都
  • 杭州
  • 武汉
  • 南京
  • 广州
  • 西安
  • 重庆
  • 深圳
  • 上海(总部)服务中心

    电话:400 1816 180

    地址:上海市徐汇区文定路218号德必徐家汇WE艺术湾B座205

    公交路线:76路、93路、138路宜山路蒲汇塘路站;205路、732路、754路南丹路宜山路站;205路、754路、830路南丹路文定路站等

    地铁路线:地铁3号线、4号线宜山路站出站470m;地铁1号线、4号线上海体育馆站出站600m。

  • 北京服务中心

    电话:400 1816 180

    地址:北京市朝阳区雅宝路7号 E园EPARK大厦508

    公交路线:乘坐公交44路外环;58路;139路;特12路外环;特2路;夜20路外环到雅宝路公交站 下车,走140米即可达到。

    地铁路线:乘坐地铁1号线、2号线到建国门站(A出口)步行1000米即可到达;乘坐地铁2号线、6号线到朝阳门站(A出口)步行1200米即可到达雅宝路7号 E园EPARK大厦。

  • 成都服务中心

    电话:400 1816 180

    地址:成都市锦江区总府路31号Z31六楼(皇冠假日酒店旁)

    公交路线:乘坐58路、98路、锦城观光3号线、熊猫快线5号线在春熙路步行街北站下 步行约281米。

    地铁路线:乘坐地铁2号线或者3号线到春熙路C口下,步行约982米

  • 杭州服务中心

    电话:400 1816 180

    地址:杭州市江干区江锦路159号 平安金融中心B座8楼

    公交路线:901路、105路环线、106路环线、9M路:富春路民心路口站 176路:市民中心北大门站,市民中心西大门站

    地铁路线:号线钱江路站;4号线钱江路,江锦路

  • 武汉服务中心

    电话:400 1816 180

    地址:武汉市珞瑜路光谷世界城广场写字楼1栋1单元14层11421室

    公交路线:乘坐18路,25路,340路,510路,518路,521路等公交车到珞瑜路湖北省中医院站下车

    地铁路线:乘坐地铁2号线至珞雄路A口出,往湖北省中医院光谷院区方向步行50米至世界城广场写字楼

  • 南京服务中心

    电话:400 1816 180

    地址: 南京市秦淮区中山东路532号金蝶科技园 H1幢308号(林客社 内)

    公交路线:5路 34路 34路区间 36路 55路 59路 y5路夜间 17路 65路 115路 118路 y17路夜间

    地铁路线:地铁2号线明故宫站1号口出,向东200米

  • 广州服务中心

    电话:400 1816 180

    地址:广州市天河区体育西路103号维多利广场B座26楼K15

    公交路线:11,18,20,230,278,293,45,583,669,886冼村路中站下。 194,40,777,778,90,观光2路花城广场路站下。

    地铁路线:乘坐地铁APM线至花城大道站下B口出,步行约500米即可到达保利威座大厦北塔。

  • 西安服务中心

    电话:400 1816 180

    地址:西安市莲湖区北大街西华门十字西南角78号嘉会广场C座4层B021号

    公交路线:4路、12路、26路、36路、37路、229路、游7钟楼北站;15路、16路、32路、102路、182路、236路、286路西华门站。

    地铁路线:地铁二号线钟楼站150米;地铁一号线/二号线北大街站700米。

  • 重庆服务中心

    电话:400 1816 180

    地址:重庆市渝中区邹容路68号大都会广场16楼1603-1604室

    公交路线:401、135、114、111、401、151、862、181、262、105、866、153、466

    地铁路线:2号线临江门站500米、1号线小什字站500米、6号线小什字站500米。

  • 深圳服务中心

    电话:400 1816 180

    地址:深圳市罗湖区书城路都市名园B栋5楼B区(只接受预约拜访)

    公交路线:101路 10路 12路 203路 214路 215路 223路 29路 3路 85路 M112路 M191路 M192路 N3路 P100路(定制公交请预约) 高快巴士200号线 高快巴士20路 高快巴士863号线到地王大厦下,步行431米即可到达。

    地铁路线:乘坐1号线/罗宝线/2号线/蛇口线到大剧院(E口)出,步行498米即可到达都市名园B栋

预约托福考试规划师