introduction to soil iafnr plant and soil sciences module
TRANSCRIPT
INTRODUCTION TO SOILIAFNR Plant and Soil Sciences Module
WHAT IS SOIL?
Traditionally, Soil is defined as… The material that nourishes and supports growing plants It can include rocks, water, snow, and even air, all of which are capable of supporting plant life.
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FORMATION OF SOIL
Five Factors of Soil Formation Parent Material-The rock or
other material in which soil is formed Glaciers Wind Water Gravity
Time Climate Organisms Topography
Organisms
Time
Topography
Climate
Parent Material
PHYSICAL PROPERTIES
Composition
Soils are made up of four substances Mineral Matter
From breakdown of rocks 45% of volume
Organic Matter Plant and Animal material 5% of Volume
Air Water
With Air makes up 50% of volume
Texture
Mineral Particles in soil are Sand, Silt, Clay
Also Stones, Cobble or Gravel Soil textures are classified as
Fine-made up of mostly clay Medium-silty or loamy in nature,
fine or course to touch Coarse-high sand contact, feel
like table salt
PHYSICAL PROPERTIES
Structure
Structure refers to the arrangement of soil particles Classified into three classes
Structureless-single grain With-structure-granular, platy etc. Structure-destroyed-puddles
Soil structure is important to the absorption of water and the circulation of air
Density and Depth
Bulk Density- the weight of oven-dry soil with is natural arrangement Influence water movement, root
depth, and other physical limitations
Soil Depth-total depth of the topsoil, subsoil, and parent material that allow root growth Depth of soil can cause a
change in crop yield
PHYSICAL PROPERTIES
Colors
Important in recognizing different soil types and characteristics Primarily due to two factors
Humus (Organic Matter)-Dark brown, almost black color in soil
Iron-affects color from weathering of minerals and can be Gray, Red, and Yellow in color
Water Relations
The size, shape, and arrangement of the soil particles and pores determine the ability of a soil to retain water. Large pores conduct water
quicker than fine pores
THE SOIL PROFILE
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SOIL FERTILITY
Nitrogen Part of the chlorophyll which
gives plants their green color Plants that lack in Nitrogen will
lose their normal green color and turn yellow Tips of lower or bottom leaves
turn yellow first
Phosphorus High need for phosphorus by
young plants near root system and seed Tips of lower or bottom leaves
turn blue-green or purple when deficient
Potassium Second to Nitrogen in amounts
used by plants Deficiencies most likely to occur
in sandy soils Browning along lower or bottom leaf
edges
Soil pH Soil pH id s measure of how acidic or basic a soil is pH scale ranges from 0-14
0-6.9 acidic 7 is neutral 7.1-14 basic
LAB ACTIVITY
SOIL TYPESJIGSAW ACTIVITY
SOIL CLASSIFICATIONS
Soils are classified just like plants
They are grouped according to their Agronomic Use- good/ poor soil for certain crops Color Organic Matter Content- mineral soil or peat soil Texture- sand or loam Moisture Condition-wet or dry
Scientific Classification 12 soil orders- used worldwide
Broken down into suborders, great groups, subgroups, families, and series Soil series- used locally
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12 SOIL ORDERS
12 SOIL ORDERS
12 SOIL ORDERS
12 SOIL ORDERS
Order Description
Alfisols Located in semiarid to moist areas, clay and minerals located in the subsurface, 10% of world land surface
Andisols Highly productive soils, contains volcanic materials, located in cool areas with moderate-high rainfall, 1% of worlds land surface
Aridisols Very dry soils, common in the deserts, 12% of world land surface
Entisols Dunes and flood planes, multiple environments, 16% of world land surface
Gelisols Permafrost near surface, common in high latitudes, 9% of world land surface
Histosols High organic matter content and saturation, common called bogs, 1% of world land surface
Inceptisols Semiarid to humid environments, located in variety of climates, 17% of world land surface
Mollisols Dark color, high organic matter content and very fertile, 7% of world land surface
Oxisols Located in subtropical and tropical regions, low fertility, 8% of world land surface
Spodosols Found under coniferous forests in humid areas, acidic and infertile, 4% of world land surface
Ultisols Humid area soil, dominated by quartz and iron and acidic, 8% of world land surface
Vertisols High content of expanding clay materials, high natural fertility, 2% of world land surface
REFERENCES
Parker, R. (2010). Plant and Soil Science: Fundamentals and Applications. Clifton Park, NY: Delmar.
United States Department of Agriculture. The Twelve Orders of Soil Taxonomy. Retrieved from http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_053588