Fertilizer costs have increased a lot over the last few decades, even more over the last couple of years. An example of this is that nitrogen fertilizer has doubled in just the last 2 years. With the way things are going it is not looking it will change for the better any time soon.
The most expensive input in warm-season forage production is commercial fertilizer. Since this is a costly resource, we need to make use of it efficiently. This will ensure that the return on the investment can be optimized for the most profits.
I will tell you that when it comes to being efficient that does not mean being the “cheapest”. Going with the lowest cost in the long run can actually end up costing the most. Here are 4 ways that you can look to optimize what fertilizer that you put out while reducing forage production costs.
Get your soil tested
Having adequate soil fertility is the one key to a successful forage and hay production. This is literally the foundation that all of the others are built on. Unless all the required nutrients are supplied in the adequate amounts then your forage production will not reach its full potential.
Soil testing is the best tool that a forage production manager has to monitor their soil fertility levels. Routinely performing soil tests can help identify nutrient deficiencies and inadequate soil pH. On the other side of this it can also indicate which nutrients are present at high enough levels for fertilizer to be skipped.
Tests conducted within the last three years will provide you with information that is current enough for you to make your decisions. It will let you know how well your pasture improvement plan is working. This is of course if you have been following the fertilizer recommendations provided for you from your results. If you did not then it may be a good idea for you to collect another soil test so you can have the most accurate measurements that you need.
After the test
Once you have the results look at what levels of the nutrients that you are wanting currently are. If they are in the optimum range then you can consider skipping the application this year. Phosphorus (P) levels in forages should be between 100 and 150 ppm. For Potassium (K) it is in the 100 to 200 ppm area. Any decisions that you make in regards to fertilizer should be made in relation to whether the field is below, within, or above the optimum range.
When you decide to apply your fertilizer is also just as important as what type that you use. The general rule here is that you do not want to apply any fertilizer on your warm-season grasses until you have 5 consecutive nights where the lows do not get below 60degs. If you apply before that time you will be feeding the weeds more than anything and that will just be a waste of money.
I go over the importance of soil testing and the steps to conduct one in a previous article “Don’t hold back your soil test”.
Choose the most adequate fertilizer source
Where you choose to get your fertilizer from can have just as much of an impact on the efficiency of your application as anything. There are several sources that are commercially available to supply Nitrogen, Phosphorus, Potassium as well as other micronutrients to forages. I emphasize again this is not an area where you want to go with the “lowest sticker price” but instead do a little math to find out which will work best for you.
The three main sources of nitrogen fertilizers used in pastures around the country are ammonium nitrate, ammonium sulfate, and urea. Biosolids and animal manures are also excellent sources of nitrogen if you prefer to go the organic route. No matter what you go with it is important to consider things like price, fertilizer effectiveness, method, and rate of application.
Example
You should calculate fertilizer costs based on dollars per pound of the nutrient you need. Breaking it down into this will give you a more “apples to apples” comparison. Here is an example that you can follow to come to your answer (disclaimer: this is just an example and you should contact your local supplier to get a price).
- Ammonium nitrate (35% N) costs $550/Ton. 2000lbs of ammonium nitrate contains 700lbs of Nitrogen (2000 X 0.35= 700). Thus the price per lb of N is $0.79 per lb of N.
Along with the costs it is important to consider the acidity potential of each N fertilizer source you may use. Regardless of which you go with N fertilization typically reduces the pH in the soil. Some however can cause this reaction more rapidly than others. So with this it is also a good idea to consider the additional costs of adding a lime application.
Manage your grazing properly
It is vital that you have a handle on the weeds that are in your pasture. Weeds compete with forages for light, water, nutrients, and space while providing no value. The way that your animals graze can play a very important role in the need for fertilizer.
Your type of grazing management can have a significant impact on your soil fertility status. Feces and urine from animals can recycle a large amount of Nitrogen, Phosphorus, Calcium, and other nutrients back into the soil. Since however grazing animals tend to spend more of their time near water, shade, and feeding areas a spread out distribution of this can be a major challenge.
Stocking rates and grazing methods, such as rotational or continuous, are important factors that may affect nutrient distribution. Generally, rotational grazing leads to a more evenly spread out distribution. The stocking rate can have an impact on things like soil compaction. This is since the more animals you have the more they will be walking over your soil.
Use legumes to your advantage
Another way to reduce your input costs without sacrificing yield is by incorporating legumes in your forages. The roots of the legumes pull Nitrogen from the air as a nutrient source for the plant to grow. The roots also release nitrogen into the soil as an available nutrient for other plants. The plant dies and releases even more nitrogen into the soil as its components decompose.
You should do some research before choosing a legume since not all legumes are the same. This will help to find which would work best for your operation. Although, fixed nitrogen can replace 25 to 75 pounds of fertilizer per acre in a typical year. A 30% stand of legume in the pasture can supply 30 to 50lbs of nitrogen per year according to the University of Wisconsin-Madison.
