Envirothon Soils

1. Envirothon Soils Dennis Brezina USDA-Natural Resources Conservation Service Resource Soil Scientist – Bryan Area Conservation…Our Purpose; Our Passion.

2. What is Soil? Soil: The combination of air, water, organic and mineral matter on the earth’s surface that is distinguishable from its parent material and can support rooted vegetation. R = Bedrock

3. Four Components of a Typical Soil 1% 25% 49% 25% Pore space remains about the same If the soil is wet>>>it contains more water As the soil dries>>>air takes its place

4. CLIMATE • MOST INFLUENTIAL FACTOR • Weather over time • Temperature and precipitation in particular • Determines the nature and speed of formation and development • High Heat, High humidity, abundant rain generally produces more development • For every 10 degrees C rise in temperature, the rate of chemical reactions doubles • Also micro-climates created because of topography

5. BIOTIC ACTIVITY • Plants and manipulation by animals • Especially Native Vegetation - Grasses vs. trees • Microorganisms Soils under forest vegetation generally hold less moisture, have lower pH and organic matter, and thus are generally lighter in color, and have lower fertility Soils under prairie vegetation hold more moisture, have higher pH and organic matter, and thus are generally darker in color, and have higher fertility

6. PARENT MATERIAL • Weathered fragments of Organic or Mineral material from which soils form • Related to Geology • Most of the eastern half of Texas was influenced by the Gulf Coast as Coastal Plain Sediments ( At least 85% of Texas was under water at one time) • Soils are derived from sandy, loamy and clayey sediments

7. Law of superposition - Steno • One of the bases of the sciences of geology, archaeology, and other fields dealing with stratigraphy. • “Layers of rock are arranged in a time sequence, with the oldest on the bottom and the youngest on the top, unless later processes disturb this arrangement.” • Danish scientist Nicolas Steno, 17th Century. http://en.wikipedia.org/wiki/Law_of_superposition

8. Law of superposition - Steno • Younger • Older The one thing this law doesn’t discuss is faulting… And the Edwards Plateau has it’s faults…

9. Parent Material, continued… gravity Colluvium • Texas has the following types of parent material: • Residual – formed in place, such as from bedrock • Colluvium – material moved by gravity • Alluvial – Deposited by rivers, creeks or streams • Marine – deposited by oceans • Eolian – deposited by wind P. 398, Brady

10. TOPOGRAPHYSlope or configuration of the land Nearly level vs. sloping - Water shedding vs. water receiving - Flat areas are generally wetter than steeper, sloping areas Different soils will occur on different landscape positions - Soils on back and shoulder slopes are generally thinner than those on summits, footslopes and toeslopes • Summit • Shoulder • Backslope • Footslope • Toeslope

11. Slope Percentage Rise over Run • Slope = rise/run x 100 = % slope • 10 ft. rise / 100 ft. run x 100 = 10% slope 10% slope 10 ft. Rise 100 ft. Run

12. Slope Percentage Rise over Run

13. TIME • Soils on flood plains and along the coast are “younger” or less-well developed • Stable landscapes have “older” more developed soils Takes about 500 years to form an inch of soil from hard parent material Geologic Yardstick of Time

14. Soil Forming Processes • Additions • Losses • Translocations • Transformations • Eluviation is movement out of a soil horizon. • Illuviation is movement into a soil horizon. P. 222, Gabler, et. al.

15. This is an excellent, broad Ecological Region Map of Texas separating the ten main ecoregions of the state: http://www.tpwd.state.tx.us/landwater/land/maps/gis/map_downloads/

16. Climate also plays a role in the Ecoregions. Thermic is the temperature that you can grow cotton, while Hyperthermic is the line for citrus http://soildata.tamu.edu/temperature.htm Rainfall likewise influences the Ecoregions. Udic is where pine production can flourish. The center of Ustic is about the line for dry-land corn. http://soildata.tamu.edu/moisture.htm

17. Edwards Plateau & Llano-Basin Area • Predominately shallow and moderately deep, alkaline, dark-surfaced soils that formed mostly under juniper-oak and mesquite-oak savannah. • Mostly used for hunting, sheep & goats.

18. Simplified Soil Profile • O = Organic Layer • A= Surface Horizon • (Most biologically active) • B = Subsoil Horizon • (Generally a color change, higher clay content and blocky structure) • C = Parent Material • (Residual, Colluvium, Alluvium, Marine or Eolian) • R = Bedrock

19. Simplified Soil Profile • A= Surface Horizon • (Most biologically active) • B = Subsoil Horizon • (Typically has higher clay content and blocky structure) • C = Parent Material • (Residual, Colluvium, Alluvium, Marine or Eolian) A B C

20. Two Basic Soil Epipedons or Surface Horizons • 1. Mollic Epipedon • Thick, Dark Surface • Color Value of 5 or less (3 or less moist) • Color Chroma of 3 or less (moist) • Dark=high organic content • Soil Order is either Mollisols or Vertisols

21. Two Basic Soil Epipedons or Surface Horizons • 2. Ochric Epipedon • Basically any other surface horizon • Light Colored Surface • Light=low organic content • Soil Order is generally Entisols, Alfisols or Inceptisols

22. Argillic Horizon • Generally have a Sandy or Loamy surface • Increase in Clay from the surface to the Subsoil • This horizon is called an ARGILLIC horizon • Sometimes called a “Claypan” • Water often perches on top of the Argillic horizon

23. SOIL TEXTURE The relative proportion of SAND, SILT and CLAY • The MOST IMPORTANT PHYSICAL PROPERTY of the soil because it determines the capacity of a soil to retain moisture and air. • Essentially impossible to change unless you remove it, or add large amounts to it.

24. The Three SOIL Particle Sizes Sand size particles are: • Largest of the soil particles • Feels gritty • Compare it to a beachball Silt size particles are: • Intermediate in size • Smooth, talcum powder feel and feels slick when wet • Compare it to a baseball Clay size particles are: • The smallest in size • Sticky and plastic when wet • Compare it to hole-punch confetti

25. Clayey Soils High Shrink-Swell Clay minerals expand when wet and shrink when dry. Cause cracks in building foundations, sidewalks, etc. • High organic content • High water holding capacity • Slower permeability • Higher runoff • Agriculturally productive • Difficult to work with More Water

26. Sandy Soils Larger pore space Low water holding capacity Rapid infiltration and permeability Higher leaching Low organic matter Low fertility Generally better drained Easy to work with This doesn’t mean that sandy soils are not as “good” as clayey soils. Sandy soils are just good for different things (peanuts, timber production, etc.).

27. SOIL COLOR Most visible soil property Soil color is written as: Hue Value/Chroma (10YR 6/3) HUE CHROMA VALUE

28. Soil Color Dark = high organic content Humus and organic matter are generally black or brown. Light = low organic content Red, yellow and brown are well drained Generally due to oxidation of iron compounds in the soil. Reds are highly oxidized. Compare it to rust on iron. When metal gets wet, as it dries (oxidizes) it turns a reddish-yellow color. Gray could mean excessive wetness The iron in soil is either removed or reduced when oxygen is removed. 1. HUE Most visible soil property 3. CHROMA 2. VALUE

29. Mottles/Redoximorphic Features Grays are iron depletions (reduced iron). • Mottles and redoximorphic features are caused by oxidized or reduced iron. • Red, orange and yellow colors are iron accumulations (oxidized iron).

30. Soil pH Ideal pH range is 5.5 to 7.5 Most U.S. soils have pH range of 4 to 8.5. In general, as rainfall increases, pH decreases pH >8.5 could mean high salt content pH<4 could mean Aluminum and Iron toxicity Add lime for soils less than pH of 5.5, and sulfur for soils above pH of 7.5.

31. Erosion Wearing away or removal of the earth’s soil or land surface. Soil moved by wind, water, ice or gravity. • Especially occurs on bare soil • Areas with more than 3 percent slope are susceptible to water erosion.

32. Types of Erosion • Sheet and Rill Erosion • Raindrop Splash http://www.public.asu.edu/~mschmeec/rainsplash.html • Wind Erosion • Gully Erosion

33. Stubble Mulch or Ridge-Till No-Till Conservation Practices = Things that Prevent Erosion Contour Farming Strip Cropping & Terracing Planting Wind Breaks

34. Preventing Raindrop Splash • Vegetative cover • Lawns, pasture or rangeland • No-Till • Stubble mulch or ridge till • Cover crops • No-Till intercepts raindrop splash almost like having grass cover. • Soil structure improves with time, and more water infiltrates and percolates through the soil.

35. Comparison of No-Till to Conventional Tillage Conventional tilled field No-Till field The clear water from the No-Till side of the field is transporting less topsoil, nutrients and pesticides. Milan Experiment Station-Milan, Tennessee

36. Preventing Sheet and Rill Erosion • Slow the speed of surface water flow • Contour farming • Terracing • No-Till, stubble mulch or ridge-till • Grassed waterways • Contour farming and terracing intercept and slow down the speed of surface water flow. • Some crops do not leave enough residue and cover to use No-Till. • Clayey soils also do not accept No-Till as well as loamy soils (hard to work).

37. Preventing Gully Erosion • Vegetative cover • Grassed waterways • No-Till • Contour farming • Strip cropping • Terracing • Grassed waterways are used all over the country to prevent all four types of erosion. • Terraces are used on steeper land to intercept and slow down the downhill flow of water.

38. Preventing Wind Erosion • Plant Windbreaks • Rotary hoes add surface roughness • Strip cropping • Each of these break the wind http://www.ewrs.org/pwc/rotary.htm

39. How can Soils affect our Water? Sedimentation in the Connecticut River after Hurricane Irene (Source: NASA) http://earthobservatory.nasa.gov/IOTD/view.php?id=52059

40. How does Erosion affect water? • Increases runoff • Less infiltration • Less uptake by plants • Sediment in streams, rivers, lakes and oceans Precipitation Runoff Infiltration

41. Soil Surveys An inventory of soils that includes maps, soil descriptions, photos and tables of soil properties and features. Used by farmers, real estate agents, land use planners, engineers and people wanting information on soil resources for land use planning.

42. The major parts of a soil survey publication... How to Use this Soil Survey Table of Contents Introduction and General Nature of the County General Soil Map & Block Diagrams Detailed soil map units Use and management and interpretive tables Classification of soils References Glossary Index to map sheets Soil maps

43. Using a Soil Survey Locate your area of interest on the map index. • Identify all of the soil map unit symbols at your area of interest, and find the soil map unit on the soil legend.

44. Detailed soil map unit description • Probably the most important description • Map unit symbol and name • Description of where it is mapped • Inclusions • Thumbnail soil description • Land uses • Soil Properties Narrative

45. How to use the Soil Survey Tables • Table of Contents has a Summary of Tables • The Tables contain information on soil properties, suitabilities and limitations, as well as management and production. • Find the Table that has the information that you are needing.

46. How to use the Soil Survey Tables Go to the table that contains the information you seek Find your map unit symbol Find the land use practice or yield data Table provides information on suitability for that soil for that particular land practice

47. Question? • HoB Houston Black will produce about 45 bushels of wheat per acre. • A bushel of wheat weighs 60 pounds. • A bushel of wheat will yield about 42 pounds of white flour. • 42 pounds of white flour will yield about 73 loaves of bread. • How many loaves of bread will 40 acres of HoB Houston Black yield? • 45 bushels X 73 loaves x 40 acres = • 131,400 loaves of bread

48. References Ag Handbook 296, Land Resource Regions and Major Land Resource Areas of the United States, USDA-NRCS (available at http://soils.usda.gov/survey/geography/mlra/index.html) Essentials of Physical Geography, by Gabler, Sager, Brazier and Wise Field Book for Describing and Sampling Soils, by Schoeneberger, Wysocki, Benham and Broderson The Nature and Properties of Soils, by Brady http://milan.tennessee.edu/ http://munsell.com/ http://photogallery.nrcs.usda.gov/Index.asp http://soilcrop.tamu.edu/ http://soildatamart.nrcs.usda.gov/ http://soils.usda.gov/ http://tpwd.state.tx.us/ http://www.beg.utexas.edu/ http://www.epa.gov/ http://www.flickr.com/photos/ http://www.lib.utexas.edu/ http://www.tx.nrcs.usda.gov/

49. Contacts • USDA-Natural Resources Conservation Service • Dennis Brezina, Resource Soil Scientist Bryan Area Office=979-846-0757 ext. 3 1716 Briarcrest Drive, suite 510 Bryan, TX 77802 dennis.brezina@tx.usda.gov • Temple State Soils Staff=254-742-9850

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