Plant Ecology Chapter 4 Soils Minerals Soil Structure
- Slides: 49
Plant Ecology - Chapter 4 Soils & Minerals
Soil Structure & Texture Soil structure physical arrangement of soil particles into aggregates Controls soil porosity
Soil Structure & Texture Soil texture proportional distribution of different-sized particles
Soil Structure & Texture
Soil Structure & Texture Loam soils have balance between sand, silt, clay Equal parts of sand silt, less clay Generally most desirable for agriculture
Soil Structure & Texture Sandy soils - >50% sand particles coarse texture Hold water, minerals poorly Warm quickly, cool quickly
Soil Structure & Texture Clayey soils - >35% clay Hold large volume of water Retain water and minerals well Also retain pesticides, pollutants
Soil Structure & Texture Poor infiltration = greater runoff Poor drainage, poor aeration Slow to warm and cool
Soil Structure & Texture Silty soils - >50% silt Intermediate in characteristics between sandy and clayey soils
Soil Structure & Texture Sand, silt particles irregular in shape Clay particles platelike or rod-shaped Clay particles have large surface-tovolume ratio
Soil Structure & Texture Particle size, shape affects porosity Pore space in sandy soils - 35 -50% Clayey soils - 5060% - smaller particle size & arrangement (cluster together)
Soil Structure & Texture Clay particles usually bear strong negative electrochemical charge Attract cations, such as important nutrients and water molecules
Soil Structure & Texture H, Ca, Mg, K, Na ions most abundant in soils in humid regions Arid soils, H ions move to last on list, Na more important All attract, hold water molecules
Soil Structure & Texture Cations attracted to clay particles partially available to plants Exchange between particles, soil water Ions can be taken up by plants from water, leached, or reattach to other particles
Soil p. H in U. S. - 3. 5 to 10 Native vegetation adapted to all p. Hs, but most ag crops grow best in slightly acidic soils Changing p. H has strong effects on nutrient and toxin availability, soil biota (bacteria, fungi)
Soil p. H Forest trees especially tolerant of acidic soils Conifers tend to increase acidity of soil (lower p. H) via decomposition of needles
Soil p. H Grasslands tend to grow on alkaline soils Low rainfall results in soils with high p. H
Soil Horizons & Profiles Soils contain layers horizons Sequence of horizons produces a soil profile O, A, B, C, R
Soil Horizons & Profiles O horizon - organic matter
Soil Horizons & Profiles A horizon - topsoil Region of maximum leaching - eluviation
Soil Horizons & Profiles B horizon - subsoil Region of maximum deposition illuviation
Soil Horizons & Profiles C horizon undeveloped mineral material
Soil Horizons & Profiles R horizon - parent material (bedrock)
Soil Development Residual soils develop in place by breakdown of bedrock Ecological succession 100 s to 1000 s of years
Soil Development Transported soils carried from some other place - wind, water, glaciers
Soil Development 5 factors determine the kinds of soils that develop in an area Climate, parent material, time, topography, living organisms
Soil order
Organic Matter, Organisms Organic matter humus - contributes, binds nutrients, retains water, acidifies soil (alters nutrient availability) Organism actions alter porosity, structure
Water in Soils
Water in Soils
Water in Soils
Water in Soils
Water in Soils Hydraulic lift - deeprooted plants pull water upward Moves out into drier, shallow soils Allows survival of shallow-rooted plants during drought, or in arid environments
Plant Nutrients Macronutrients and micronutrients Essential vs. beneficial Two most important for plants: nitrogen and phosphorus
Nitrogen Fixers Free-living nitrogen fixers cyanobacteria Flooded rice paddies, some surface soils
Nitrogen Fixers Symbiotic nitrogen fixers Rhizobium, Bradyrhizobium on legumes - root nodules Frankia on non-legumes Cyanobacteria external to some plant roots loose associations
Phosphorus in Soils Availability not directly related to amount present in soil Phosphorus bound in ways that make it unavailable to plants Bound to clay particles, metal ions, immobilized by microbes
Evergreen vs. Deciduous Evergreens often characteristic of nutrient -poor soils, soils subject to drought Deciduous leaves require higher investments in photosynthetic enzymes, other proteins
Mycorrhizae Symbioses between various fungi, roots of terrestrial plants Extremely common, widespread Approach for dealing with phosphorus limitation, other nutrient shortages
Mycorrhizae Two major groups Endomycorrhizae Ectomycorrhizae Endo- are most common, especially arbuscular mycorrhizae
Mycorrhizae Arbuscular mycorrhizae - most abundant where phosphorus is limited, in warm, dry climates Important in tropical ecosystems, and for crop pants - woody and herbaceous Fungal body grows inside root cells, with hyphae extending outward
Mycorrhizae Arbuscular mycorrhizae associations not highly specific same fungus may have many plant host species, or one host may have several fungal associates
Mycorrhizae Ectomycorrhizae woody plants, especially temperate conifers Hartig net between root cells, mantle network of hyphae outside root
Mycorrhizae Fungal hyphae increase nutrient uptake from soil Transfer nutrients to root cells of host plants
Mycorrhizae Increased uptake, especially of phosphorus, results from higher surface area, and production of enzymes that release phosphorus from clay
Mycorrhizae - more good Improve metal uptake Improve water uptake Break down soil proteins Protect roots from toxins Protect plant from fungal, bacterial diseases
Mutualism or Parasitism? Fungi get carbon, energy from plant host Plant gets nutrients, other benefits Either “partner” can function as parasite at times - plant sheds fungus when times are good, or fungus gives little to plant
- Minerals in the soil
- Living soil vs dead soil
- Four major spheres of the earth
- The rate of weathering depends upon the area's ____.
- Latosol soil profile
- Soil
- Anchorage soil
- Aridisols are soils characteristically found in _______.
- Timbering in loose soil
- Clorpt
- What is soil
- How does the study of soils help evaluate natural hazards?
- 4 components of soil
- Which is not true of laterite soils
- Soil layers
- Ashley soils
- Pedalfer soil
- Chapter 4 population ecology test answer key
- Plant nutrition and soil science
- Chapter 8 vitamins and minerals
- Chapter 2 minerals
- Chapter 22 plant structure and function answer key
- Chapter 21 plant structure and function
- Chapter 35 plant structure growth and development
- Primary growth and secondary growth in plants
- Chapter 23 plant structure and function
- Plant introduction
- Plant breeding for disease resistance
- Plant introduction in plant breeding
- Tronsmo plant pathology and plant diseases download
- Tronsmo plant pathology and plant diseases download
- Albugo eye
- Chapter 52: an introduction to ecology and the biosphere
- Section 1 community ecology
- Chapter 56 conservation biology and restoration ecology
- Phosphorus cycle pearson education
- Chapter 54: community ecology answer key
- Chapter 53 population ecology
- Chaparral climograph
- Chapter 5 evolution and community ecology answer key
- Chapter 36 population ecology
- Principles of ecology section 2 flow of energy
- Principles of ecology chapter 2
- Chapter 2 principles of ecology answers
- Chapter 4 population ecology answer key
- Chapter 54 community ecology
- Chapter 53 population ecology
- Chapter 55 ecosystems and restoration ecology
- Chapter 5 evolution and community ecology
- Chapter 5 evolution and community ecology