1 / 34

Introduction to the Soils of PA

Introduction to the Soils of PA. Troy Area High School Mr. Schanbacher. Essential Questions. UEQ: What is soil? How are soils formed? What is parent material? What are soil horizons? How do I measure soil texture? What are active fractions? What are soil aggregates?

Download Presentation

Introduction to the Soils of PA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Introduction to the Soils of PA Troy Area High School Mr. Schanbacher

  2. Essential Questions • UEQ: What is soil? • How are soils formed? • What is parent material? • What are soil horizons? • How do I measure soil texture? • What are active fractions? • What are soil aggregates? • Why is soil water important? • What is mottling and how is it related to soil drainage class? • Why is soil pH an important property for soil formation? • How are soils classified? • How do I utilize a soil survey? • What is a capability class and subclass? • What is a limiting factor? • How do I measure slope?

  3. What is Soil? • Soil is a naturally occurring mixture of mineral and organic ingredients with a definite form, structure, and composition. The exact composition of soil changes from one location to another. The following is the average composition by volume of the major soil ingredients: • 45% Minerals (clay, silt, sand, gravel, stones). • 25% Water (the amount varies depending upon precipitation and the water holding capacity of the soil). • 25% Air (an essential ingredient for living organisms). • 5% Organic matter or humus (both living and dead organisms).

  4. How are soils formed? • The five soil-forming factors are: • Parent material • Climate • Time • Living organisms • Landscape position • Relief

  5. What is Parent Material • The material the soil develops from • Bedrock • Limestone Soils: Great for agriculture • Sandstone: Coarse and dry out quickly • Shale: Fine Textured, Acidic and Low in Nutrients • With fertilizers they can be farmed • Support mixed forests • Much has been lost to mining • Residual Soils: • Transported Parent Material • Glaciated: Glacial Till (fragipans=bad for drainage) • Aelian(loess): wind • Colluvial: Gravity (Footslopes)(also have fragipans) • Alluvial: Sediment carried by flowing water (great for agriculture…bad for buildings

  6. Climate and Time • Plant and Animal Life • Rainfall: more life…quicker chemical reactions • Temperature: Warmer and More Moisture=faster soil development Think rain forest vs. tundra This process takes centuries…

  7. Living Organisms • Vegetative Matter • Roots (Living and Dead) • Deeper the better…Why? • Water Movement: • Litter • Provide food for and are broken down by fungi, bacteria, insects, earthworms, and burrowing animals. • Change organic material into usable nutrients for plants • Microbes and humus (broken down organic matter) act as a glue for soil

  8. Landscape Position • Water and Wind move soil • Steepness, Length, and Shape of slope influences the rate at which water moves into or over soil. • Erosion: the movement of soil (unprotected soils)

  9. Assignment: • Use the Soil Survey of Bradford and Sullivan Counties to complete the following assignment: • Explain how each of the five soil forming factors have influenced soil formation in Bradford County? You should write at least 3 sentences for each factor. (25 Points)

  10. What are Soil Horizons?

  11. Soil Horizons Continued.. • O Horizon - The top, organic layer of soil, made up mostly of leaf litter and humus (decomposed organic matter). • A Horizon - The layer called topsoil; it is found below the O horizon and above the E horizon. Seeds germinate and plant roots grow in this dark-colored layer. It is made up of humus (decomposed organic matter) mixed with mineral particles. • E Horizon - This eluviation (leaching) layer is light in color; this layer is beneath the A Horizon and above the B Horizon. It is made up mostly of sand and silt, having lost most of its minerals and clay as water drips through the soil (in the process of eluviation). • B Horizon - Also called the subsoil - this layer is beneath the E Horizon and above the C Horizon. It contains clay and mineral deposits (like iron, aluminum oxides, and calcium carbonate) that it receives from layers above it when mineralized water drips from the soil above. • C Horizon - Also called regolith: the layer beneath the B Horizon and above the R Horizon. It consists of slightly broken-up bedrock. Plant roots do not penetrate into this layer; very little organic material is found in this layer. • R Horizon - The unweathered rock (bedrock) layer that is beneath all the other layers.

  12. How do I measure soil texture? • Soil texture: the percent sand, silt and clay in a soil sample • Clay= <0.002mm • Silt= 0.002mm-0.05mm • Sand= 0.05mm-2mm

  13. Just another way to look at particle sizes…

  14. Amount of sand, silt and clay in a soil. • Nutrient holding capacity • Water holding capacity • Drainage • Tilth Soil Texture Classification

  15. How do I measure soil texture? • Feel Test • Ribbon Test • Soil Sieve • Chemical Test.

  16. Sand • Large pore spaces in soil • Drains rapidly • Remains soft and light so roots penetrate and spread easily • Too much sand will not hold water or nutrients for plants • Has high bearing strength so it makes a stable foundation for buildings

  17. Silt • Optimal amount of water retention and air circulation for agriculture. • Silt is easily carried by the wind…loess soils are silty soils

  18. Clay • Extremely good water holding capacity. • Coats larger soil particles and binds them together to create soil aggregates. • High percentage of clay is said to be heavy soils b/c it creates drag on the plow and plant roots • Compaction smashes soil aggregates and closes channels for air and water. • The soil becomes impermeable, slippery, muddy when wet, hard and cracked when dry and plants will not grow! • Clay soils do not make good foundations b/c clay changes in volume and crack as moisture content changes

  19. Blocky Granular Prismatic Platy Columnar Single Grained Massive Mineral Organic Air Water Soil Structure • Arrangement of sand, silt and clay in a soil • Compaction • Tilth • Root growth • Water movement

  20. Active Fractions • Clay and Organic matter increase the Cation Exchange Capacity (CEC) of soil. • Clay and Organic Matter carry a negative charge (-) and electrically attract positively charged(+) ions that are floating in soil water. • These ions such as Ca, K, and Mg are then available for plants • Increases fertility • Reduces fertilizer (nutrient) losses • Cleans effluents from septic tanks

  21. Cation Exchange Capacity

  22. Soil Water • All about the texture of the soil • Drainage conditions are indicated by soil color • Depth to Mottling (patches of gray and orange discolorations caused by soil that is saturated for part of the year) • Often dependent on landscape position • The further down the hill the poorer the drainage • Building on poorly drained soil will lead to wet basements and septic issues • Plants will have shallow root sytems

  23. >40”=Well Drained • 20-40”= Moderately Well Drained • 10-20”=Somewhat Poorly Drained • <10”=Very Poorly Drained

  24. Twelve Soil Orders • Gelisols - soils with permafrost within 2 m of the surface • Histosols- organic soils • Spodosols- acid forest soils with a subsurface accumulation of metal-humus complexes • Andisols- soils formed in volcanic ash • Oxisols- intensely weathered soils of tropical and subtropical environments • Vertisols- clayey soils with high shrink/swell capacity • Aridisols- CaCO3-containing soils of arid environments with subsurface horizon development • Ultisols- strongly leached soils with a subsurface zone of clay accumulation and <35% base saturation • Mollisols- grassland soils with high base status • Alfisols- moderately leached soils with a subsurface zone of clay accumulation and >35% base saturation • Inceptisols- soils with weakly developed subsurface horizons • Entisols- soils with little or no morphological development

  25. Soil Color

  26. Why is soil pH important? • Soil pH of 6.5 is optimal for most crops • PA Soils tend to be acidic because of acid rain • Our need for lime! • Further West=Less Rain

More Related