Soil Testing

Why Test Your Soil?

  • Testing your soil is a simple, easy way to determine if your soil and yard are in balance with the right amount of nutrients.  A good yard has an environmental balance.  It allows the rain to collect deeply into the soil and prevents unnecessary runoff even in heavy rains.
  • Economically, a good yard needs only mowing and occasional fertilizer.  Too much fertilizer is not only a waste of money, but the excess can run off into the storm drains and ultimately into the Illinois River.

Here’s what soil testing “scientifically” evaluates:

  • Provides a scientific basis for regulating available plant nutrients to optimize plant growth
  • Provides a basis for efficient use of fertilizers to avoid over application

Two important values measured by a soil analysis are “soil pH” and the “available plant nutrients.” Soil pH is a measured value which represents the level of acidity or alkalinity of a soil. Different types of plants have various pH ranges at which plant nutrients are available.  The soil analysis identifies pH problems and provides recommendations for correcting them as well as recommendations on types and amounts of fertilizer to apply to optimize plant growth.

Contents Of Your Soil Analysis Report:

  • Table 1 lists the concentration in parts per million (PPM) and pounds per acre (lb/acre) of available plant nutrients
  • Table 2 Provides an outline of your soil’s physical and electrical properties
  • Table 3 Provides recommendations for the application of plant nutrients (not fertilizer amounts) as well as liming recommendations
  • Table 4, 5 & 6 are additional crop notes which provide information related to the timing of nutrient application and rate adjustments for specific cultural conditions

Example For Calculating Lawn Fertilizer Amounts:

Recommendations (Table 3) for lawns are provided in pounds per 1000 square feet. Before calculating the recommended amount of fertilizer, measure the lawn’s total area. If your lawn is 50 ft. x 100 ft. then the total area equals 50 ft. x 100 ft. = 5000 sq. ft.
If the recommendation is to apply 2 lb. of N per 1000 sq. ft., then you will need a total of 10 lb. of N to obtain coverage of your 5000 sq. ft. lawn 2 lb. x 5000 sq. ft. /1000 sq. ft. = 10 lb. total
Now the question is where to obtain 10 lb. of N. At the local garden center you find a 60 lb. bag of 34-0-0 "lawn fertilizer.” The sequence of the three numbers separated by hyphens is the guaranteed analysis and is always given in the specific order of percent nitrogen, percent phosphate, (P205) and percent potash (k20) in the bag.

Use the formula:

(% Nutrient / 100) x total lbs. of fertilizer = lbs. of nutrient in the bag (34% N/100) x 60 lbs. = 20.4 lbs. of N in the bag.
You’ve already determined that you need 10 lbs of N to fertilize your 5000 sq. ft. lawn and the 60 lb. bag contains 20.4 lbs. of N. You will need 29 lbs. of fertilizer, or about half of the 60 lb. bag (60 lb. bag / 20.4 lbs. N per bag) x 10 lbs. N = 29.4 lbs fertilizer.

Another way of looking at it:

If you want to apply fertilizers at a rate of 2 lbs. per 1000 sq. ft. and you have a 60 lb. bag of fertilizer with a grade of 34-0-0, then 60 lb. x 34/2 lb. x 1000 sq. ft. = 10200 sq. ft. total coverage. Remember: 

  • Always apply fertilizer and pesticides according to the product’s label or nutrient manager’s recommendation
  • Accurately calibrate equipment prior to application
  • Apply product to the lawn only!! Sweep excess product from driveways, sidewalks or the street back onto the lawn. Do not allow product to go down the storm drain
  • To prevent unwanted spills, reseal product containers and store

You can drop off your soil for testing at the following UA and OSU Extension offices in the watershed:

Adair County:
Stillwell, Ok
Courthouse
220 W. Division Street
8:00 - 4:30, M-F,
$10/sample
918-253-4332

Benton County:
Bentonville, AR
Cooperative Extension Service
Hwy 102 W
8:00 - 4:30, M-F,
No charge - Free
479-271-1060

Cherokee County:
Tahlequah, OK
Fairgrounds
908 S. College Ave
8:00 -4:30, M-F
$10/sample
918-456-6163

Delaware County
Jay, Ok
Fairgrounds
38267 US Hwy 59
8:00-4:30, M-F
$10/sample
918-253-4332

Sequoyah County
Sallisaw, Ok
Courthouse
120 E. Chickasaw
8:00-4:30 M-F
$10/sample
918-775-4838

Washington County
Fayetteville, AR
Cooperative Extension Service
2536 McConnell Ave
8:00 - 4:30, M-F
No charge - Free
479-444-1755