INTRODUCTION TO SOIL IAFNR 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. Image retrieved from:

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 Image retrieved from:

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  acidic  7 is neutral  basic

LAB ACTIVITY

SOIL TYPES JIGSAW 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

Image retrieved from: e:SoilTexture_USDA.png e:SoilTexture_USDA.png

12 SOIL ORDERS

OrderDescription AlfisolsLocated in semiarid to moist areas, clay and minerals located in the subsurface, 10% of world land surface AndisolsHighly productive soils, contains volcanic materials, located in cool areas with moderate-high rainfall, 1% of worlds land surface AridisolsVery dry soils, common in the deserts, 12% of world land surface EntisolsDunes and flood planes, multiple environments, 16% of world land surface GelisolsPermafrost near surface, common in high latitudes, 9% of world land surface HistosolsHigh organic matter content and saturation, common called bogs, 1% of world land surface InceptisolsSemiarid to humid environments, located in variety of climates, 17% of world land surface MollisolsDark color, high organic matter content and very fertile, 7% of world land surface OxisolsLocated in subtropical and tropical regions, low fertility, 8% of world land surface SpodosolsFound under coniferous forests in humid areas, acidic and infertile, 4% of world land surface UltisolsHumid area soil, dominated by quartz and iron and acidic, 8% of world land surface VertisolsHigh 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