Land Judging Handout
Objective of land Judging – The goal of land judging is to evaluate a given area called a field and
determine its land class and then the best way to conserve the land while still producing crops and
forage.
Land Classes – There are eight land classes
- Classes I, II,III,IV, are for cropland
- Classes V,VI, and VII are for pasture
- Class VIII is for wildlife
Land Class descriptions:
Class I land – This is the perfect piece of cropland.
- Nearly level
- Takes no water from other areas of land
Class II Land – Very good cropland with more slope than Class I
Class III Land – Cropland with generally more slope than class II.
- May be class III because of erosion
Class IV Land – Cropland with more slope or erosion than class III
Class V Land – Pasture land that is in a bottom and too wet to farm.
Class VI Land – Pasture land that is too steep to farm,
-When combined with texture slope may be less than class IV
Class VII Land – Steep pasture land
Class VIII Land – Not suitable for any agricultural use
- Only way is to be “Very Frequently Ponded”
Land Class Factors
Depth of Soil – This is measure of the depth of the overall root zone of plants in a soil.
-In Eastern Nebraska ALWAYS MARK DEEP!!
Surface Texture – This is your determination of the amount of Sand, Silt, or clay particles in a soil.
- Texture is the single most important soil characteristic
- Texture is determined by ribboning a small sample of soil
- Heavy and fine terms are the same soil
- Coarse and Light are the same soil
- Heavy or fine soils have more clay and little or no sand.
-Light or coarse soils have little or no clay and lots of sand.
-Medium soils have mostly silt particles.
Characteristics of Sand, Silt, and Clay
Sand
- The largest soil particle
- can be seen with the naked eye
- can be felt with your fingers
- has a gritty feel
- does not stick together well making wind erosion a problem
- have low water holding capacity making dryness a problem
-have rapid permeability making leaching a problem
- loosely packed together
- are lighter in color, appearing grey or tan
Silt
- is medium sized soil particle
- higher attraction for water than sand
- hold more water and hold it tighter than sand
-have higher nutrient holding capacity as well
- has a floury feel when dry
- dry clods are broken by your fingers
- silt particle have a spongy feel when wet
Clay
- Cannot be seen with the naked eye
- have high water and nutrient holding capacity
- are so tightly packed that water runs in very slowly
- Feel slippery when very wet
- Feel very sticky as they dry a bit
- will stick to your hands and can’t be brushed off easily
- dry clods are very difficult to break with your fingers
Surface Texture Classes
Fine
- Includes – Sandy clay, clay and Silty Clay
– these soils form very hard clumps when dry
- plastic and sticky when wet
- will form long flexible ribbon when wet
-at least a 2.5 inch ribbon
Moderately Fine – Includes sandy clay loam, clay loam, and silty clay loam
- Forms a ribbon 1-2 inches long
- forms clods that are broken with your fingers
- often very dark color
- often are mostly silt and clay
Medium -
Includes loam, silt loam, and very fine sandy loam
- Will form a ribbon that is about 1” long
- will easily break in your fingers and you will be able to pulverize it in your hand
- Feels floury when dry
- Feels spongy and squishy in your hand as your ribbon it.
- mostly silt particles
- Will be able to see sand ‘sparkles” in it as you hold it to the sun
Moderately Coarse - Includes Sandy Loam. Fine Sandy Loam, Coarse Sandy Loam
Coarse
Will be mostly sand particles
Will feel gritty in your hand when dry
Will very easily break clods in your fingers
Can feel and see individual grains of sand
Will not ribbon, but crumbles out of your hand
Will form a cast when dry that breaks easily
- Includes Loamy very fine sand, Loamy fine sand, a loamy sand, coarse sand and very
fine sand
-Very high amounts of sand
- Will not stain your hand as it is handled
-Can see and feel lots of sand
-Will not ribbon, won’t form any crumbles or clumps
Permeability of Subsoil
- This soil factor refers to the ability of a soil to take in water.
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This is important as soils with slow permeability do not take in water fast enough to
prevent excessive runoff.
Soils with rapid permeability allow nutrients and water out of the root zone.
For land judging purposes, permeability is determined by ribboning the subsoil sample. You will then
use the texture determination of the subsoil to select a permeability class.
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Very Slow Permeability – not used in our area, only VS soils are along Missouri River
bottom near Tekamah.
Slow Permeability – Will ribbon like a “Fine “ topsoil , with a ribbon about 3 “ long
Moderately Slow Permeability – Will ribbon like a “Moderately Fine” topsoil. It will
have a 2 inch ribbon and have a great deal of clay.
Moderate Permeability - Will ribbon like a “Medium” topsoil. It will have a bit
more clay than a topsoil. It will have some Sand particles visible.
Moderately Rapid Permeability – These soils ribbon like the “Moderately Coarse”
top soils. They will have sand that you can see and feel.
Rapid Permeability – These will have no soil structure and be loose fine sand. Will
not ribbon at all.
Slope
Slope refers to amount of change in the elevation from on the field. In land judging
events, commonly stakes are placed 100’ apart and you are to determine the difference in
elevation between the two points.
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The formula for slope is Rise/Run
If the Run is 100’ , all you have to do is determine “Rise”.
Slope is really a key factor in determining Land Class
If there is a 5 ‘difference in elevation in 100” , the slope is 5%.
The steeper the land the faster the run off
Affects time water is exposed to the soil and infiltration.
Even coarse textured soils with rapid permeability will have run off with enough
slope.
If slope stakes are 50 feet apart, you must double your answer.
I try to check my slope observations 3 or 4 times on each whole a
Slope Classifications
Nearly Level – less than 2% slope
Gently Sloping – 2-6 % slope
Moderately Sloping – 6-11% slope
Strongly Sloping – 11-17% slope
Steep – 17- 30% slope
Very Steep – over 30% slope
Thickness of Surface Soil
Thickness of surface sol is used in two places on your card.
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It is marked in its own section where you determine the class from your
observations of the soil profile while standing in the pit.
It is used to determine the amount and class of erosion in the Erosion section.
Thickness of Surface Soil Classes:
Thick - Topsoil more than 12” thick
Moderately thick – Topsoil 6 to 12” thick
Thin – Topoil less than 6” thick
Erosion
Erosion the process where soil particles are detached from the surface and moved
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Wind and water are the 2 main causes of erosion.
Raindrops start erosion as the loosen soil particles and make them prone to erosion
through the runoff of excess rain water.
Erosion leads to decreased soil fertility, costly repairs and lower yields
You use the “Original Surface Soil Thickness’ given at the start of each whole to
determine erosion class.
Severe Erosion may drop a field a Land Class, check your capability Chart carefully.
Erosion Classes
None to Slight – Less than 25% of Topsoil gone.
Moderate – 25% to 75% of Topsoil gone
Severe – More than 75% of topsoil gone
Very Severe – More than 75% of Topsoil gone PLUS gullies
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A gully is defined as a water pathway which is not crossable the machinery.
I divide the original thickness by 4 to set the class breaks in my mind for each class
Putting it all together:
Using the field factors from your observations you can now determine the land class.
The Capability Charts are a hierarchical elimination style chart. You start with the proper
landscape position as given in the Field Instructions. From there you will eliminate each section
as you go and do not return to a previous section once you have passed it.
1. Select the landscape position as given in the field instructions
Upland and stream terrace
Upland and terrace depressions
Floodplains and sandhill meadows
2. Select the proper depth of the soil you determined
Deep and very deep
3. Select the Surface texture you determined from the provided sample box
As you move down the chart to find the proper texture, you eliminate each
section as you pass it by. So if you have a moderately coarse texture you will use the
section indicated, or move lower in the chart as you look at the next property.
4. Select the permeability you determined, remember, only go down or across in the chart.
5. Select the Drainage, Flooding and Ponding as provided in the field instructions.
6. Select the row with the slope you determined.
7. Select the erosion which you determined.
8. Read the land capability class from the row. Check for any exception statements.
As a check for the determination, a general description is offered in the last column. Read
through this description. Compare it to what you have observed in the field and soil pit. If this
does not fit what you saw, you may want to go back and try working through the chart again,
check your field determinations, or check the information you noted from the field
You are now ready for section 3
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