Chapter 5 The Terrestrial Environment

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Chapter 4 The Terrestrial
Environment
陸地的環境
1
4.1 Life on Land Imposes
Unique Constraints
陸地上的生命承受獨特的限制
2
陸地環境對生命的限制
• 乾燥效應。(desiccation)
• 重力作用。(gravity)
• 環境因子的變動大小(例如:溫
度)。
3
The giant kelp: Macrocystis pyrifera
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A redwood wood: Sequoia sempervirens
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4.2 Plant Cover Influences the
Vertical Distribution of Light
植物的覆蓋影響光線的垂直分佈
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7
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植物對光線的吸收及反射情形
13
leaf area index (LAI)(葉面積指數)
14
Leaf area index (LAI)
葉面積指數
• 定義: 葉的表面積除以植物在地表的
投影面積 (m2 leaf area/ m2 ground
area) .
• A leaf area index of 3 would mean that
there are 3 m2 of leaf area over 1 m2 of
ground area.
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「葉面積指數」高低
的意義何在?
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葉片的生長方向影響其截留陽光的量
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紅木森林在地表部分的可利用光線的變化情形 18
Levels of photosynthetically active radiation (PAR),
within and above a yellow-poplar stand over a year. 19
4.3 Soil Is the Foundation
Upon Which All Terrestrial
Life Depends
土壤是所有陸地生命依賴的基礎
20
Soil definition(土壤的定義)
• Soil is a natural product formed and
synthesized by the weathering of
rocks and the action of living
organisms.
• (土壤是岩石的風化作用與生物
活動形成的天然產物)
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Soil definition (土壤的定義)
• Soil is a collection of natural bodies of
earth, composed of mineral and
organic matter and capable of
supporting plant growth.
• 土壤是地表聚積的自然體,由無機
物及有機物組成,能支持植物的生
長。
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4.4 The Formation of Soil
Begins with Weathering
土壤的形成開始於風化作用
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Weathering (風化作用)
• Mechanical weathering(物理風化作
用): breaks down rock and minerals
into smaller particles.(透過物理作用
將岩石或礦物變成小顆粒)
• Chemical weathering(化學風化作
用):
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4.5 Soil Formation Involves
Five Interrelated Factors
土壤的形成包含五個相關的因子
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土壤形成的五個因子
• Parental material (母岩)
• Climate (氣候)
• Biotic factors (生物因子)
• Topography (地形)
• Time (時間)
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4.6 Soils Have Certain
Distinguishing Physical
Characteristics
土壤具有某些可區分的物理性質
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Soil texture(土壤特徵(組成))
• Soil texture is the proportion of
different-sized soil particles.
•
•
•
•
Gravel(砂礫): larger than 2.0 mm.
Sand(沙): from 0.05 to 2.0 mm.
Silt(泥沙): from 0.002 to 0.05 mm.
Clay(黏土): less than 0.002 mm.
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Soil texture(土壤特徵)
• Gravel is not part of the fine fraction of
soil.
• A soil texture is the percentage (by weight)
of sand, silt, and clay.
• Clay controls the most important
properties of soils, including its water
holding capacity, and the exchange of ions
between soil particles and soil solution.
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A soil texture chart, which shows the
percentages of clay, silt, and sand in
the basic soil texture classes.
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4.7 The Soil Body Has
Horizontal Layers, or
Horizons
土壤有水平的層狀結構
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土壤的層狀結構
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一般的土壤剖面
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土壤剖面圖
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4.8 Moisture-Holding
Capacity Is an Essential
Feature of Soils
水分保持能力是土壤的重要特徵
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Moisture-holding capacity of soil
• Saturated(飽和): the amount of water
exceeds what the pore space of soil can hold.
• Field capacity(田間容量): Water fills
all the pore spaces of soil and is hold there
by internal capillary forces.(水分以毛細
作用充滿土壤中所有的孔隙)
• Capillary water(毛細水): Water held
between soil particles by capillary forces.
(水分以毛細作用為土壤所保留)
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Moisture-holding capacity of soil
• Wilting point (WP): The moisture
level of soil decreases to a point at
which plants can no longer extract
water.
• 枯萎點:土壤中的水分減少到植物
無法從中獲得水分,此土壤之含水
量稱為枯萎點。
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Moisture-holding capacity of soil
• Available water capacity (AWC): The
amount of water retained by the soil
between field capacity and wilting
point.
• 可利用的水容量:
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Water content of three different soils at wilting
point (WP), field capacity (FC), and saturation.
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4.9 Ion Exchange Capacity Is
Important to Soil Fertility
離子交換容量對土壤肥沃度很重要
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Ion(離子)
• Cation(陽離子): with positive
charge(s)(帶正電荷的離子)
• Anion(陰離子): with negative
charge(s)(帶負電荷的離子)
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Ion exchange(離子交換)
• Ion exchange capacity(離子交換容量): The
total number of charged sites on soil particles
within a volume of soil.(一定體積土壤內的
帶電荷離子位置總數目)
• Colloids(膠狀體):土壤中帶負電荷的離子
• Cation exchange capacity(陽離子交換容量)
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土壤中的陽離子交換過程
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Ion exchange
• The lyotropic series :
• Al3+ > H+ > Ca2+ > Mg2+ > K+ =
NH4+ > Na+
• Hydrogen ions (H+ ) effect: Al3+
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Soil acidity
• Typically, soils range from pH 3
(extremely acid) to pH 9 (strongly
alkaline).(土壤的酸鹼值一般從pH
3-9)
• Soils just over pH 7 (neutral) are
considered basic, and those of pH 5.6
or below are acid.
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4.10 Basic Soil Formation
Processes Produce Different
Soils
基礎的土壤形成過程中產生不
同的土壤
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世界上主要土壤類型的剖面及基本描述
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世界上主要土壤類型的剖面及基本描述
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主要土壤類型在世界上的分佈
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五種主要土壤的形成過程
•
•
•
•
•
Laterization: 紅土化
Calcification: 石灰化
Salinization: 鹽化
Podzolization: 灰壤化
Gleization
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Laterization(紅土的形成過程)
• 炎熱、多雨的氣候迅速風化岩石,
大量雨水造成離子、養分的高淋蝕,
只留下鐵及鋁的氧化物。
• 鐵的氧化物是土壤紅色的原因。
• Ultisol
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Laterization (紅土的形成過程)
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Calcification(石灰化)
• 發生在植物的蒸散作用超過降雨量的情
況,使土壤中溶解性鹽類上升。
• 降雨又將鹽類往土壤深層帶。
• 在土壤B層形成礦物沈積,通常是
CaCO3 ,形成所謂鈣化層(Caliche)。
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Calcification(石灰化)
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Salinization(鹽化)
• 發生在乾燥地區,形成過程類似鈣
化作用。
• 鹽類沈積在地表或接近地表處。
• 發生在沙漠、海岸或灌溉的農業區。
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Salinization(鹽化)
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Podzolization(灰壤化)
• 發生在寒冷、潮濕的中緯度地區的針葉
林環境。
• 針葉樹的有機質形成強酸性物質,酸淋
洗掉土壤A層中的陽離子及鐵、鋁氧化
物,使A層下方成白色或灰色。
• Spodosol。
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Podzolization(灰壤化)
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Gleization
• 發生在高降雨量但排水不良之低窪
地區。
• 排水不良使的有機物質大量堆積,
形成的有機酸與土壤中鐵產生化學
作用,形成黑色或藍灰色土壤。
• Gelisol。
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Gleization
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農業與土壤鹽化
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Dry land salinization
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