Clif Little
Extension Agent
Agriculture/Natural Resources Agent
Guernsey County
Jeff McCutcheon
Extension Agent
Agriculture/Natural Resources Agent
Perry County
Fertilizer can be a significant out-of-pocket expense in the maintenance of hay and forage crops. Frequently, cost is given as the prime reason why a producer does not fertilize hay and forage crops for maintenance. Producers can save money on fertilizer applications if they compare the total cost of applying different fertilizer blends.
Economically speaking, all fertilizers are not created equal. Let's say you have decided that this year you want to stockpile a field of tall fescue for winter grazing. You remember a recommendation that you should apply 50 pounds of actual nitrogen per acre. The local fertilizer dealer gives you these prices on three different nitrogen sources:
| Urea | @ | $190/ton |
| Ammonium Nitrate | @ | $240/ton |
| Ammonium Sulfate | @ | $167/ton |
What fertilizer would be the best choice if you wanted to apply 50 pounds of nitrogen per acre? At first glance, you might choose Ammonium Sulfate. The actual value of each as a nitrogen source is quite different, as illustrated in this example:
| Urea | = | 46-0-0 |
| Ammonium Nitrate | = | 34-0-0 |
| Ammonium Sulfate | = | 21-0-0-2 |
| Urea: | $10.71 x 50 | = | $535.50 |
| Ammonium Nitrate: | $18.09 x 50 | = | $904.50 |
| Ammonium Sulfate: | $20.59 x 50 | = | $1,029.50 |
In this case, urea was actually the best value. This was an example to demonstrate the steps in determining what the total cost of applying a given fertilizer would be. Please remember that applications of urea-based fertilizers in summer may result in significant losses of nitrogen due to volatilization. If one-half inch of rain is not received in three to four days after an application of urea, then volatilization of the urea can be significant. For more information on proper use of nitrogen fertilizers, please refer to Selecting Forms of Nitrogen Fertilizer, Agronomy Fact Sheet 205. Using these steps to compare fertilizer cost may save producers hundreds, if not thousands, of dollars annually. Fertilizing when plants can best utilize nutrients, managing your nitrogen source, and comparing the total cost of fertilizer blends will put more money in your pocket. It should be noted that the calculations presented here do not consider the value of other nutrients available in these fertilizer blends. If you are fertilizing for multiple nutrients, then the same process can be used.
The previous example was for one nutrient, and each of the choices had one nutrient to compare. How can you compare mixed blends of fertilizer? Compare the following different fertilizer sources:
15-15-15 @ $210.72/ton
19-19-19 @ $220.60/ton
What fertilizer would be the best choice?
Rarely do crops need the three primary nutrients on a one- to-one-to-one basis. It is recommended that a soil-test analysis and possibly a tissue analysis be utilized to determine the crop's needs for nutrients and the rates at which those nutrients should be applied. A soil test is the best way to determine the nutrient needs of a soil. Several laboratories in and around Ohio offer soil-testing services for a nominal fee. Contact your local Extension office for a complete list. Please refer to Bulletin E-2567 or Fact Sheet AGF 206-95 for information on correct sampling procedures.
Soil tests provide information about the nutrient level of the soil and the amounts of lime and fertilizers necessary to achieve a particular yield goal. In addition, educational comments for particular crops are provided on the report form.
What happens after you have taken a soil test and have the results? How do you determine the best fertilizer to apply? Let's look at a soil-test report that came from a field at the Eastern Ohio Resource Development Center (EORDC). This is a field of fescue with a yield goal of three tons per acre. The results say that this year we need to apply:
125 pounds of nitrogen, 50 pounds of phosphate, and 265 pounds of potash per acre.
The results also say that we should split the nitrogen application into a spring and a fall treatment. Since you need to split the nitrogen application, you decide to split the phosphate and potash application as well. Now you will need to apply:
62.5 pounds of nitrogen, 25 pounds of phosphate, and 132.5 pounds of potash per acre in the spring and in the fall. To avoid the potential for grass tetany, you decide to apply the spring application after first cutting.
You call the local fertilizer dealer and get the following prices.
| 19-19-19 | @ | $220.60/ton | |
| Urea | 46-0-0 | @ | $190.00/ton |
| Triple Super Phosphate | 0-46-0 | @ | $249.90/ton |
| Potash | 0-0-60 | @ | $187.00/ton |
| DAP | 18-46-0 | @ | $265.00/ton |
What would be the best choice or combination to use?
| 19-19-19 | @ | $220.60/ton | |
| Urea | 46-0-0 | @ | $190.00/ton |
| Triple Super Phosphate | 0-46-0 | @ | $249.90/ton |
| Potash | 0-0-60 | @ | $187.00/ton |
| DAP | 18-46-0 | @ | $265.00/ton |
Table 1. Percentage of Fertilizer Nutrients and Content |
||||
|---|---|---|---|---|
| Source | N | P2O5 | K2O | Secondary & Micronutrients With Concentrations Greater Than 1% |
| Anhydrous Ammonia |
82.0
|
-
|
-
|
-
|
| Ammonia Nitrate |
33.5
|
-
|
-
|
|
| Ammonia Sulfate |
21.0
|
-
|
-
|
23.0 S
|
| Urea |
46.0
|
-
|
-
|
-
|
| Aqua Ammonia |
20.0-25.0
|
-
|
-
|
-
|
| Nitrogen Solutions |
20.0-32.0
|
-
|
-
|
-
|
| Urea Formaldehyde |
38.0
|
-
|
-
|
-
|
| Calcium Nitrate |
15.5
|
-
|
-
|
19.4 Ca, 1.5 Mg
|
| Superphosphate |
-
|
47.0
|
-
|
14.0 Ca, 1.4 S
|
| Ammonia Phosphate |
11.0
|
48.0
|
0.2
|
1.1 Ca, 2.2 S
|
| Diammonium Phosphate |
18.0
|
47.0
|
-
|
|
| Muriate of Potash |
-
|
-
|
60.0-62.0
|
47 Cl, 1.2 Mg, 18.0 S
|
| Potassium Magnesium Sulfate |
-
|
-
|
21.0
|
11.0 Mg, 23.0 S
|
| Potassium Nitrate |
13.0
|
-
|
44.0
|
|
| Ammonium Nitrate-lime |
20.0
|
-
|
-
|
7.3 Ca, 4.4 Mg, 4.0 S
|
| Magnesium Sulfate |
-
|
-
|
-
|
2.2 Ca, 10.5 Mg, 14.0 S
|
| Gypsum (Calcium Sulfate) |
-
|
-
|
0.5
|
22.3 Ca, 17.0 S
|
| Elemental Sulfur |
-
|
-
|
-
|
30.0-99.0 S
|
| Basic Slag |
-
|
8.0-12.0
|
29.0 Ca, 3.3 Mg, 21.0 Mn
|
|
| Kieserite |
-
|
-
|
-
|
1.5 Ca, 18.2 Mg
|
| Dolomite |
-
|
-
|
-
|
21.0 Ca, 18.2 Mg
|
| Limestone (calcitic) |
-
|
-
|
0.3
|
32.0 Ca, 3.0 Mg
|
| Borax |
-
|
-
|
-
|
11.0 B
|
| Copper Sulfate |
-
|
-
|
-
|
33.0 Cu, 13.0 S
|
| Iron Sulfate |
-
|
-
|
-
|
20.0 Fe, 12.0 S
|
| Manganese Oxide |
-
|
-
|
-
|
41.0-68.0 Mn
|
| Manganese Sulfate |
-
|
-
|
-
|
23.0-28.0 Mn, 13.0 S
|
| Zinc Oxide |
-
|
-
|
-
|
50.0-80.0 Zn
|
| Zinc Sulfate |
-
|
-
|
-
|
12.0-18.0 Zn
|
| Source: The Fertilizer Handbook, by The Fertilizer Institute, Washington, D.C. | ||||
The decision as to what nutrients to purchase for forage crops should be based on soil and possibly tissue tests. Differences in the value of crop nutrients can be extreme. For this reason, we recommend that you purchase the nutrients needed as indicated through proper analysis. Compare each nutrient source for the concentration of nutrients and follow the best management practices associated with the application of nutrients described in OSU Extension Bulletin 609. If planting, the amount of nitrogen supplied by the previous crop should also be considered. Table 2 lists nitrogen credits that should be subtracted from the nitrogen fertilizer recommendation if not previously done by the soil testing laboratory.
Table2. Nitrogen Available from Previous Crop (lb/acre) |
|
|---|---|
| Previous Crop | N Credits |
| Corn, Small Grain | 0 |
| Soybeans | 30 |
| Grass Sod/Pasture | 40 |
| Forage Legume | |
| Avg. Stand (3 plants/ft2) 40 + [20 x (plants/ft2)] | |
| Max. 140 | |
| Source: Extension Bulletin E-2567 | |
For more information on forage fertility or if you have specific questions on testing, contact your local Extension office.
Michigan State University, The Ohio State University, Purdue University. Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat & Alfalfa. Extension Bulletin E-2567.
Potash & Phosphate Institute. 1996. Soil Fertility Manual. Norcross, Georgia.
The Fertilizer Institute. 1983. The Fertilizer Handbook. The Fertilizer Institute, Washington, D.C.
Ohio State University Extension. Ohio Agronomy Guide. Bulletin 472.
The authors would like to thank the individuals listed here for reviewing the manuscript: Mark Sulc, OSU Extension Forage Specialist; Hank Bartholomew, Southern Ohio Grazing Coordinator; Ed Vollborn, Leader, Grazing; Jay Johnson, OSU Extension Fertility Specialist; Joy Ann Fischer, Communications and Technology; and Dave Miller, East District Farm Management Specialist. Also, thank you to Carla Wickham, Office Assistant, OSU Extension, Noble County.
Step 1.
Determine fertilizer recommendations based on yield goals and soil test
values.
Crop to be grown ______________________________________________
Yield goal ____________________________________________________
Fertilizer recommendations based on soil test.
pH _______________
N ________________ lb./A
P205 ______________ lb./A
K20 _______________ lb./A
It may be necessary to convert Phosphate P205 to elemental P or K20 to elemental K. Work in the same terms as the soil-test results.
P205 x 0.44 = Elemental P
K20 x 0.83 = Elemental K
Step 2.
Select a fertilizer blend or nutrient source.
| ________ lbs. of fertilizer to spread = |
____________lb. of nutrient recommended by soil test |
| ____________percentage of nutrient in source (decimal form) |
Example: 0-46-0 source we are comparing
| _____________________ = (lb. of fertilizer to spread) |
__25 lb. P205 recommended by our soil test__ |
| pounds to apply per acre = 54.3 lb./A |
Do the same steps for nitrogen and potash. These steps will tell you how much fertilizer you need.
If you are looking at purchasing nitrogen for a new planting, you need to consider residual nitrogen from the previous crop and past application of manures. Look at Table 2 and deduct the nitrogen credits from the nitrogen recommended on the soil test.
Step 3.
Calculate the tons of fertilizer needed.
___2,000 lb. per ton_____ = # of acres a ton will cover
lb./A to spread from Step 2
Example: From Step 2:
_2,000 lb. per ton_ = 36.8 acres we can cover
54.3 lb./A to apply
If we needed to fertilize 10 acres:
10 acres x 54.3 lb./A = 543 lb. of fertilizer needed.
| _____________ (acres to spread) |
x | ___________________ (lb. of fertilizer per acre) |
= | Total lb. of fertilizer needed |
Do this for each major nutrient needed.
Step 4.
Calculate cost per acre.
| _______________ (fertilizer cost/ton) |
÷ | ________________ (# of acres you can |
= | fertilizer cost per acre |
| spread per ton of fertilizer, Step 3) |
| Example: 0-46-0 @ | $249.90/ton | ÷ | 36.8 acres per ton | |
| $249.90 | ÷ | 36.8 | = $6.79 per acre cost of fertilizer |
Step 5.
Calculate the spreading cost per acre.
| ________________ (Spreading cost/ton) |
÷ | ___________________________ (# of acres you can spread per ton) |
= | spreading cost per acre |
Example: Spreading cost $6.00/ton
$ 6.00 ÷ 36.8 acres per ton = $0.16 spreading cost per acre
Step 6.
Calculate the total cost of fertilizer per acre.
| ___________________ (Fertilizer cost per acre) |
+ | ____________________ (Spreading cost per acre) |
= | ________________ (Total cost per acre) |
|
Step 4
|
Step 4
|
*Spreading cost can be significant.
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Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
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