University of KentuckyCollege of Agriculture
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Description of Soil Test Summaries

A summary of soil test P, K, Ca, Mg, and Zn, and soil pH values are provided for each county and the six major physiographic regions in Kentucky. The summary is for agricultural soil samples submitted to the University of Kentucky soil test laboratories over a three year period. Soil test nutrients were obtained with the Mehlich III test and are presented in units of lbs/acre. Soil pH was obtained with a glass electrode in a 1:1 mixture of soil and water that was left to set for 1 hour.

Each summary has a table showing the number of samples, the median soil test result and the percent of soil samples tested within defined ranges. The table has this information for all samples and for samples arranged according to the crop that was said to be grown. The crops represented are corn, soybean, forages, tobacco, and wheat for the agricultural samples (A).  For the home lawn and garden samples (H), the crops represented are vegetables, fruits, turf and landscape.  For the commercial horticulture samples (C), the crops represented are flowers, nurseries, vegetables, and fruits and nuts  For details on what codes from the sample information forms were considered for each of these categories see the section "Details on Soil Test Summaries" below.

The median is presented for the soil test results. The median should not be confused with the average. Since distributions of soil test results were often skewed, a median is a better representation of the middle of the data than the average. Half of the samples can be said to be above the median and half of the samples are below the median.  The soil test ranges are classified as vLow (very low), Low, Med (medium), lowHigh (lower high values), medHigh (medium high values), and hiHigh (upper high values).  Any soil testing medium or lower would result in a recommendation of lime or fertilizer to correct a deficiency.

Details on Soil Test Summaries

Physiographic regions

Soil test summaries are provided for the whole state and six physiographic regions within the state.  These regions are Eastern Mountains, Bluegrass, Eastern Pennyroyal, Western Pennyroyal, Purchase, and Western Coal Fields.  Data is organized according to the county the samples were received from.  Since some counties may represent more than one physiographic region, the summaries on physiographic regions are not that exact.  An example of this is Todd county.  The northern part of the county is in the Western Coal Fields and the southern part is in the Western Pennyroyal.  A county was assigned to a physiographic region based on the predominant region in the county.  All of Todd county data was assigned to the Western Pennyroyal.

For a detailed discussion of the physiographic regions of Kentucky go to:

Category details

For each county and region, all data is presented in addition to data sorted by crop and soil management.  Data was sorted according to the information provided on the soil test information sheets that accompany the sample.  The primary crop codes used for sorting data by crop are as follows:

Sorted crop = crop code #, code description


Keyword used in granddatabase: corn

Corn = 18, corn

Keyword used in granddatabase: soybean

Soybeans = 50, soybean

Keywords used in granddatabase: alfalfa,grass,fescue,forage,lespedeza,clover,timothy,trefoil,crownvetch

Forages = 4, alfalfa/grass; 5, cool season grass; 22, fescue; 78, fescue/lespedeza (multiple); 76, forage crops (multiple); 28, lespedeza; 9, lespedeza/grass; 2, alfalfa; 10, bermudagrass, common; 12, bermudagrass, improved; 14, bluegrass; 70, white clover; 56, timothy; 55, timothy/red clover; 52, sudangrass; 48, sorghum sudangrass; 35, orchardgrass/red clover; 36, orchardgrass; 37, orchardgrass/white clover; 25, bluegrass/white clover; 24, forage sorghum; 16, birdsfoot trefoil; 20, crownvetch; 23, fescue/white clover; 72, white clover/grass; 19, warm season grass; 40, red clover/grass; 38, red clover 

Keyword used in granddatabase: tobacco

Tobacco = 58, burley tobacco; 60, dark tobacco

Keywords used in granddatabase: wheat,small grains

Wheat = 66, wheat; [new: 11, small grains; 46, small grains/corn; 13, small grains/soybeans]


Keywords used in granddatabase: annuals,perennials,bulbs,other flowers

Flowers = 2, annuals; 4, perennials (not bulbs); 6, bulbs; 96, other flowers

Keywords used in granddatabase: azaleas,conifers,deciduous,evergreen,hollies,rhododendrons,other nursery

Nurseries = 10, azaleas; 12, conifers, junipers; 14, conifers, pines; 16, conifers (not pines or junipers); 18, deciduous shrubs; 20, deciduous trees; 22, evergreen shrubs, broadleaved; 24, evergreen trees, broadleaved; 26, hollies; 28, rhododendrons; 97, other nursery plants

Keywords used in granddatabase: asparagus, beans, cole, sweet, cucumbers, eggplant, greens, melons, onions, peppers, potatoes, rhubarb, root, squash, tomatoes, other vegetables

Vegetables = 32, asparagus; 34, beans (snap, dry, lima, etc.); 36, cole crops (broccoli, etc.); 38, sweet corn; 40, cucumbers; 42, eggplant; 44, greens (collards, kale, etc.); 46, muskmelons (cantaloupes); 48, onions (green & bulb); 50, peppers (bell and pimiento); 52, potatoes; 54, rhubarb; 56, root crops (beets, carrots, etc.); 58, squash & pumpkins; 60, sweet potatoes; 62, tomatoes; 64, watermelons; 68, other vegetables 

Keywords used in granddatabase: apples,berries,brambles,cherries,currants,grapes,peaches,pears,pecans,plums,walnuts,other fruits

Fruits and Nuts = 72, apples; 74, blueberries; 76, brambles; 78, tart cherries; 80, currants and gooseberries; 82, grapes; 84, peaches; 86, pears; 88, pecans; 90, plums; 92, strawberries; 94, walnuts; 99, other fruits and nuts


Keyword used in granddatabase: vegetable

Vegetables = 2, vegetable garden

Keywords used in granddatabase: apples,peaches,other tree,brambles,grape,berries

Fruits = 4, apples; 6, peaches; 8, other tree fruits; 10, brambles; 12, grape arbor; 14, strawberries; 16, blueberries

Keywords used in granddatabase: grass,fescue

Turf = 18, Kentucky bluegrass; 20, tall fescue; 22, fine fescue; 24, creeping bentgrass; 26, perennial ryegrass; 28, bermudagrass; 30, zoysiagrass

Keywords used in granddatabase: deciduous,evergreen,ground,flower garden,roses,azalea

Landscape = 46, deciduous tree; 48, deciduous shrub; 50, needled evergreen tree or shrub; 52, broadleaved evergreen tree or shrub; 54, ground covers; 56, flower garden; 58, roses; 60, azalea/rhododendron

Details on break between data categories

The groupings of soil test values are shown below. 

Soil P

% vLow, <=10

% Low, >10 and <=30

% Med, >30 and <=60

% lowHigh, >60 and <=80

% medHigh, >80 and <=200

% hiHigh, >200

Soil K

% vLow, <=100

% Low, >100 and <=200

% Med, >200 and <=300

% lowHigh, >300 and <=450

% medHigh, >450 and <= 1000

% hiHigh, >1000

Soil pH

% vLow, <=5.0

% Low, >5.0 and <=5.5

% Med, >5.5 and <=6.2

% lowHigh, >6.2 and <= 7.0

% medHigh, >7.0 and <= 8.0

% hiHigh, >8.0

Soil Ca

% Med,<=500

% lowHigh, >500 and <=4000

% medHigh, >4000 and <=8000

% hiHigh, >8000

Soil Mg

% vLow, <=10

% Low, >10 and <=30

% Med, >30 and <=60

% lowHigh, >60 and <=500

% medHigh, >500 and <=1000

% hiHigh, >1000

Soil Zn

% vLow, =0

% Low, >0 and <=1

% Med, >1 and <=6

% lowHigh, >6 and <=30

% medHigh, >30 and <=100

% hiHigh, >100

Princeton P test

Before 2000, soil samples tested at the Princeton lab would report a Mehlich III soil test P value of 201 for any result above 200.  The reason for this was that the colorimetric method used for P was not accurate above 200.  This does not affect the summary for soil test P since the % of samples above 200 is presented and the median is not affected by actual values of outlying data.