FFA Soils Presentation Summer 2015
Ag Contest - Slope
Ag Contest - Landform
Ag Contest – Texture, Surface
Soil Texture • Relative proportion of sand, silt and clay in a soil sample • Does not include organic matter
Soil Separates • Most soils have a combination of soil particles sizes • Sand • Silt • Clay
Texture ( Particle Size Distribution ) • Important for determining suitability for various uses • Considered a basic property because it doesn’t change
Soil Texture Classification Systems • USDA Soil Texture Classification System • Unified Soil Classification System • AASHTO (American Association of State Highway and Transportation Officials )
Particle Sizes Sand • Clay: less than 0.002 mm • Silt: 0.002-0.05 mm • Sand: 0.05-2 mm Silt • 0.05 – 0.1 mm very fine . • 0.1 – 0.25 mm fine Clay • 0.25 – 0.5 mm medium • 0.5 – 1 mm coarse • 1 – 2 mm very coarse • Gravels: 2-75 mm • Cobbles:75-250 mm Sand Silt Clay • Stones: 250-600 mm • Boulders: >600 mm Dime Frisbee Beachball
Texture Determination • Laboratory Methods • Pipette method • Hydrometer method • Field • “Feel” of soil when moistened and worked • Graininess, coherence, smoothness, stickiness • Ribboning behavior
Sand + Silt + Clay = 100% 34 % Sand Texture = 33 % Silt CLAY LOAM 33 % Clay
FFA Land Judging Texture • Old Contest • New Contest • 3 textures • 5 textures • Sand (sand, loamy sand) • Coarse (sand, loamy sand) • Clay (sandy clay, clay, silty • Moderately Coarse clay) (sandy loam) • Loam (silt, silt loam, loam, • Medium (loam, silt loam, sandy loam, sandy clay loam, silt) clay loam, silty clay loam) • Moderately Fine (sandy clay loam, clay loam, silty clay loam) • Fine (sandy clay, clay, silty clay)
Triangle Comparison
Ag Contest – Texture, Subsoil
Ag Contest – Structure, Surface
Ag Contest – Structure, Surface • Soil Structure is the result of soil particles that bind together to form aggregated soil peds. Structure is a very important characteristic of the soil because it can allow or disallow good air and water movement, and allow for good root penetration.
Structure Types
Granular
Blocky
Platy
Single Grained
Massive
Ag Contest – Depth of Topsoil
What is a soil horizon? • Soil material that has been acted upon by the soil formation factors, so that properties have been changed • Master Horizons • Subordinate designations within master horizons
Master Horizons • O – organic matter • A – mineral & organic matter (topsoil) • E – eluviation • B – accumulation, structure (subsoil) • C – little or no development • R – hard bedrock
Ag Contest – Depth of Topsoil • Topsoil is the uppermost part of the soil, which is most favorable for plant growth. It is typically rich in organic matter and as a result darker in color.
Ag Contest – Drainage Class
Redoximorphic Features • Redoximorphic features are red, yellow and gray colored depletions and concentrations that are indicative of a saturated zone within the soil profile. Redox depletions are gray in color (chromas of < 2) where elements solubilized by anaerobic or reducing conditions have been removed. The redox depletions are the indicator of where the water table is located. Redox concentrations are the red or red-yellow concentrations of iron oxides. Redox features are described by their presence, abundance, and contrast.
Redoximorphic Features
Redoximorphic Features Concentrations and Depletions
Ag Contest – Drainage Class
Ag Contest – Drainage Class
Ag Contest – Depth to Restrictive Feature
Ag Contest – Depth to Restrictive Feature • Any layer that limits water and roots altogether, or into vertical seams and plains of weakness. The following are examples that could be looked at as restrictive, but ANY layer limiting water or roots can be considered a restrictive feature. • Dense Glacial Till • Fragipans • Dense Clay Deposits. • Bedrock • Coarse Sand or Gravel * The above are only examples of layers that could be considered restrictive. Other layers not listed could still limit water and roots, and would still be considered a restrictive feature.
Ag Contest – Compaction
Ag Contest – Compaction
Ag Contest – Infiltration
Ag Contest – Infiltration • For the purpose of this contest, infiltration will be evaluated based on the texture and structure of the topsoil. • Rapid : Soils with rapid infiltration are coarse textured with any structure in the surface. • Moderate : These soils are moderately coarse with any structure, medium textured soils with granular and blocky structures, and moderately fine textures with granular structure. • Slow : These soils are moderately fine textured with blocky structure, and fine textured with granular or blocky structure. • Very Slow : These soils are medium, moderately fine, and fine textured soils with platy or massive structure in the surface.
Ag Contest – Infiltration Structure Single Grained Granular Blocky Platy Massive Coarse Rapid Rapid Rapid Rapid Rapid Mod. Coarse - Moderate Moderate Moderate Moderate Texture Medium - Moderate Moderate Very Slow Very Slow Mod. Fine - Moderate Slow Very Slow Very Slow Fine - Slow Slow Very Slow Very Slow
Ag Contest – Living Organisms
Ag Contest – Living Organisms
Ag Contest – Practices – Erosion – Cover Crops BMP • Cover crops with fine root system should be utilized to reduce soil erosion. Condition to call for BMP • Any of the following present: >2 - 18% slopes, flood plain, medium surface texture, single grained, platy or massive soil structure, topsoil depth less than 8”, poorly and very poorly drained soils, very shallow to restrictive features, slow or very slow infiltration, few living organisms.
Ag Contest – Practices – Erosion – No Till / Strip Till / Maintain Residue BMP • Residue should be maintained at the surface to protect soil surface from erosion. Condition to call for BMP • Any of the following present: >2 - 18% slopes, single grained, platy, or massive soil structure, topsoil depth less than 8”, SWP drained soils, shallow and very shallow to restrictive features, slow or very slow infiltration.
Ag Contest – Practices – Erosion – Grassed Waterway BMP • Grassed waterways should be constructed and/or maintained to control erosion. Condition to call for BMP • Should be used where water runoff from two adjacent slopes concentrates and flows at erosive rates which could create gullies. Slopes should be evaluated within the flagged area.
Ag Contest – Practices – Erosion – Contour farming / Strip Cropping BMP • Contour farming / strip cropping should be used to slow erosion. Contour farming should be utilized on 2 to 18% slopes, and strip cropping should be added to slopes from 6 to 18%. Condition to call for BMP • Should be used on land with broad uniform slopes from >2-18%, moderately well and well drained soils. – Slopes should be evaluated within the flagged area.
Ag Contest – Practices – Erosion – Permanent Pasture / Woodland BMP • Seeding of recommended grasses and or legumes should be done. Best management practices include mowing and controlled grazing. Condition to call for BMP • Should be used when slopes are >18 to 25%.
Ag Contest – Practices – Erosion – Permanent Woodland BMP • Land should be planted with adapted trees Condition to call for BMP • Should be used when slopes are greater than 25%
Ag Contest – Practices – Erosion – Riparian Buffers / Buffer Strip BMP • Land should be vegetated with recommended grasses and or legumes to protect stream/water from runoff from adjacent land. Condition to call for BMP • Should be used in floodplain landscapes.
Ag Contest – Practices – Erosion – Surface Drainage BMP • Spinner and open ditches should be utilized to move sitting and or ponded water from landscape. Condition to call for BMP • Should be used when all of the above are present: nearly level land where infiltration is slow or very slow, and poorly or very poorly drained.
Ag Contest – Practices – Erosion – Heavy Use Pads BMP • If used as a livestock feeding or watering area, heavy use pads should be constructed to protect the pasture and ensure herd health. The damaged areas are highly susceptible to erosion. Condition to call for BMP • Should be used on medium, moderately fine, and fine surface textured soils that are somewhat poorly, poorly or very poorly drained.
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