February, 2003
Volume XIX Issue 1

Inside ...
Fertilizer Management Tips………………………………...Page 2
Reprinted From '84, Phosphorus Fertilizer Placement……Page 3

Fertilizer Management Tips Offered
With Prospects for Higher Anhydrous Costs

Producers across America are likely to see higher nitrogen fertilizer costs this year. And, the culprit of higher nitrogen fertilizer costs is, of all things, natural gas prices.

As most producers know, nitrogen is created from anhydrous ammonia and anhydrous is created by combining natural gas, air, high temperature and intense pressure. Unfortunately, natural gas prices are increasing dramatically due to increased demand in the northeast and the use of natural gas to produce electricity.
The bottom line is we can't do much about the cost of natural gas, but we can utilize good fertilizer management to more efficiently use the nitrogen available to us.
To minimize the cost of your nitrogen this year, while maximizing its effectiveness, we offer the following management tips:

  • Have a comprehensive soil analysis conducted by Ward Laboratories to determine how much residual nitrate is available for plant use. We recommend samples from 0 to 8" for the topsoil and 8"-36" for subsoil. Further, it's important to get a representative sample of 15 cores for each sample area for both topsoil and subsoil.
  • Consider the amount of nitrogen available from any past legume crops (soybeans, alfalfa, dry beans) that can provide fertilizer for this year's crop. Crop residue from legumes including soybeans, will offer some nitrogen for new crops. As a rule of thumb, soybean residue will provide a "credit" of 40 lbs. per acre in nitrogen, alfalfa offers a "credit" of 100-120 lbs. per acre and dry beans can provide a "credit" of 25 lbs. per acre.
  • Split your nitrogen application to maximize its efficiency. Ideally, 1/3 to 1/2 of your nitrogen should be applied at or before planting with the remainder applied during the growing season. In every case, your goal should be to have the entire nitrogen requirement applied by tasseling of corn or heading of milo. Splitting your application makes the fertilizer more efficient by increasing your yield or reducing the overall rate of application.
  • Finally, knife-in liquid nitrogen which is clearly the most efficient method of liquid application.

Ward Professionals Offer Hints For
Top Dressing Fertilizer For Wheat

Every year at this time, the professionals at Ward Laboratories field dozens of calls from wheat producers about how much nitrogen is needed in a top dressing operation.
And, while it is too late to conduct a soil nitrate test, there are some rules of thumb to follow which will allow you to provide adequate top dressed fertilizer for your crop.
Since wheat generally grows when the weather is cool, producers should not expect much nitrogen help from past legume crops like you would expect from summer crops.
Generally, producers need to figure on 2.4 lbs. of nitrogen per bushel of wheat for crop development. If you conducted a soil nitrate test last fall prior to planting and you applied nitrogen in the fall, you have the information you need to calculate an early spring top dress application. If you didn't conduct a fall soil test or fall application, assume you have 50 lbs. of nitrogen/acre available in the soil.
Calculate your spring application need using the following formula:

Your Yield Goal x 2.4 -50 lbs. (or known quantity) = lbs. per acre needed in the spring

Timing of the above application is critical with the optimum application time as near dormancy break as possible. In many situations, nitrogen can be applied before dormancy break, but not in frozen fields on sloping lands.

20 years