SOIL TEST INFORMATION SHEET NO. T-610

Prepared by Extension Horticulturist Thomas J. Koske

Athletic Fields, Fairways, Sod, Lawns and Establishment

1.	If values of P or K read low or very low, split the application into two or three topdressings adding these nutrients in April, June and/or August.

2.	Apply 1 pound of N per 1000 square feet every three to four weeks until desired density is obtained, then apply N every five to six weeks (April-September) to keep desired growth.  Exception on carpet grass or centipede:  these two grasses need only a half pound of N per 1000 square feet applied two or three times per year.  Do not try to darken a naturally light grass by keeping it well fed.  This leads to thatch decline and pest problems.

3.	If slow-release materials are used, apply at longer time intervals.

4.	If lime is required and Mg rates are low, choose dolomitic  (“high mag”) lime.

5.	If a soil test shows low Mg and is high or medium in pH and Ca, add Mg using potassium-magnesium-sulfate as your source of potassium this season; or use Epsom salt.

6.	Regular feedings with ‘turf’ blends of fertilizer can be used to supply the nutrients specified.  These turf blends are fertilizers in the ratio of higher N, lower P and moderate K levels.

7.	If no P2O5 is recommended, apply little or preferably no phosphorus.  This is especially true for centipede and carpet grass.

8.	Contact your county agent for additional information and help in your fertilization program.  The agent also receives a copy of this report for the parish office files.

Understanding Fertilizer

	Fertilizers come in different strengths and blends, the three numbers on the bags show the percent by  weight of the three major nutrients. The first number is always the percent of nitrogen (N). The second is always the percent phosphorus (P) as expressed in phosphate called P2O5 equivalent and thus is not pure P.  The third number is the percent of potassium (K) expressed in the oxide called K2O equivalent.

	The higher the number the stronger the nutrient is in the fertilizer. You could apply more of a weaker fertilizer to get the amount of needed or less of a stronger fertilizer.

	Blended fertilizers have more than one nutrient like 0-20-20 or 8-24-24.  A complete fertilizer is one which has some of all three nutrients like 8-24-24.  Muriate of potash is 0-0-60 while concentrated super phosphate is 0-42-0.  Nitrogen sources might be ammonium nitrate 33-0-0, ammonium sulfate 20-0-0 or urea 46-0-0.  Other fertilizer materials are potassium sulfate 90-0-50), DAP (18-46-0), IBDU (31-0-0), SCU (32-0-0), UF (38-0-0), bone meal (2-20-0) or cottonseed meal (6-3-2).  About seven pounds of cow manure can substitute for one pound of 8-8-8.

	Dividing the percent into 100 gives the pounds of the fertilizer needed to supply one pound of that nutrient.  Take 8-8-8 for example (100 divided by 8 = 12.5).  Therefore, 12.5 pounds of 8-8-8 provides a pound each of N, P2O5 and K2O.

	The ratio of a fertilizer refers to the comparison of these numbers to each other.  Different crops and soils may need different ratios.  For example 8-8-8 is a 1-1-1 ratio while a 5-10-15 fertilizer is a 1-2-3 ratio showing a generally low N, moderate P and higher K.

	Application rates given n pounds per acre can be seen in pounds per 1000 square feet if you divide by 44.  Example:  264 lbs/ A= 264/44 or 6 lbs/1000 sq. ft.