LAND JUDGING

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LAND JUDGING
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Land Classification

• The Soil Conservation Service uses a
  classification system to describe the capability
  of the soils to produce crops.

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SCS CAPABILITY CLASSES

• There are 8 SCS land capability classes. Each
  class is based on what the land may be used for
  and what is required to maintain the
  classification

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LAND CAPABILITY CLASSES

• Class I-Cultivated crops
• Class II-Cultivated crops
• Class III-Cultivated crops
• Class IV-Cultivated crops
• Class V-Pasture
• Class VI-Pasture
• Class VII-Forestry
• Class VIII-Wildlife Recreation

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FACTORS AFFECTING LAND CLASS

• Slope
• Topsoil thickness
• Erosion
• Topsoil texture
• Permeability of subsoil
• Drainage
• Effective depth

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SLOPE CATEGORIESfor South Georgia

• Range Land Class
• Nearly level 0-2 I
• Very gentle 2-5 II
• Gentle 5-8 III
• Sloping 8-12 IV
• Strongly Sloping 12-17 VI
• Steep gt17 VII
• Very Steep NA NA

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TOPSOIL THICKNESS

• Category Range Land Class
• Extremely Thick gt40 III
• Very Thick 20-40 I
• Thick 10-20 I
• Moderate 5-10 I
• Thin lt5 II
• Topsoil thickness is measured from the soil
  surface to the 1st texture change.

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EROSION

• The percentage of original topsoil which has
  eroded.
• Determined by subtracting the actual topsoil from
  the original and dividing the eroded by the
  original and multiplying by 100.

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EROSION CATEGORIES

• Category Range Land Class
• None to slight lt25 I
• Moderate 25-75 II
• Severe gt75 III

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SOIL TEXTURE

• Soil is made up of 3 particles sand, silt clay
• There are 3 categories of texture
• Fine-smooth, sticky with no grit, will form a 2
  inch or longer ribbon
• Medium-between fine coarse, will form a ball
  and show some finger marks, will form a short
  ribbon
• Coarse-sandy, will not form a ribbon

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PERMEABILITY OF SUBSOIL

• The ability of air water to move through the
  subsoil. Based on subsoil texture.
• Rapid-coarse texture gt20
• Moderate-medium texture subsoil
• Slow-fine texture subsoil

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DRAINAGE

• Refers to surface internal drainage
• As a general rule, the quicker the soil can be
  tilled following a good rainfall the better the
  drainage.
• Color is the best indicator of drainage
• Bright colors (reds yellows) indicate good
  drainage
• Dull colors (grays browns) indicate poor
  drainage

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DRAINAGE CATEGORIES

• Category Looks
• Excessively drained Coarse texture for over 40
• Well-drained No gray mottles in top 30
• Moderately well-drained No gray mottles in top
  20
• Somewhat poorly drained No gray mottles in top
  10
• Poorly drained Gray matrix or gray mottles in
  top 10
• Very wet Surface water

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DRAINAGE LAND CLASS

• Category Land Class
• Excessively drained III
• Well-drained I
• Moderately well-drained II
• Somewhat poorly drained III
• Poorly drained IV
• Very Wet V

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EFFECTIVE DEPTH

• The depth to which plant roots can easily
  penetrate. Usually the combined thickness of the
  topsoil and subsoil.
• Hard pans and plow pan layers may affect root
  depth.
• The presence of roots is a good indication of
  effective depth.

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EFFECTIVE DEPTH RANGE

• Category Range Land Class
• Deep Roots over 40 I
• Moderate Roots from 20-40 II
• Shallow Roots from 10-20 III
• Very Shallow Roots lt10 IV

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LAND TREATMENT PRACTICESVegetative

• Use conserving improving crops
  occasionally-Always on class I
• Use conserving improving crops 1/2 of
  time-Always on class II
• Use conserving improving crops 2/3 of
  time-Always on class III
• 4. Use conserving improving crops 3/4 of
  time-Always on class IV

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• 5. Prevent residue burning-Always on classes I,
  II, III, IV
• 6. Provide mulching with crop residue-Always on
  classes I, II, III, IV
• Use strip crops-On II, III IV if terraces are
  not used D slopes if terraces are used
• Use crop rotation-Always on classes I, II, III,
  IV

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• 9. Control weeds, bushes trees-Always on
  classes I, II, III, IV, VI
• 10. Establish recommended grass and/or legumes-On
  pasture if lt 50 of the plot is covered by a
  desirable species
• 11. Improve present stand of pasture-Always on
  class VI when practice 10 is not used
• 12. Control grazing-Always on class VI
• 13. Fence the pasture-Always on class VI

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1. Use artificial reforestation-On class VII with no
   trees or if stand is poor seed trees are absent
2. Use natural reforestation-Always on class VII
   applies to current future growth
3. Use prescribed burn occasionally-Always on class
   VII
4. Protect trees from wildfires-Always on class VII
5. Control forest insects diseases-Always on class
   VII
6. Protect trees from animal damage-Always on class
   VII

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1. Control undesirable species-Always on class VII
2. Harvest trees by clear cutting-On VII with a
   mature stand or if it has merchantable trees of
   an undesirable species no merchantable trees of
   a desirable species
3. Harvest trees by selective cutting-Always on
   class VII applies to current or future growth

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LAND TREATMENT PRACTICESMechanical

1. Terrace the field-On II, III IV when slope gt 2
   topsoil lt 20 inches
2. Maintain field terraces-Always when 23 is used
3. Establish vegetative waterways-Always when 23 is
   used

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1. Construct diversion terraces-On I, II, III, IV
   VI if an up-slope water problem exists
2. Plow cultivate on the contour-Always on
   cropland pasture
3. Control existing gullies by special
   methods-Always on cropland and on pasture when
   present

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LAND TREATMENT PRACTICESPlant Nutrients

1. Apply lime-On I, II, III, IV if pH lt 6.0 on
   pasture if pH lt 6.5
2. Apply manure-On I, II, III, IV pasture when
   available
3. Apply nitrogen-Always on classes I, II, III, IV
   pasture
4. Apply phosphorus-On I, II, III, IV VI if
   phosphorus is less than very high
5. Apply potash-On I, II, III, IV VI when potash
   is less than very high