Manure: Can You Afford It?
Manure is generally considered affordable and if you are a dairy, poultry, or hog farmer, you have lots of it and want to use it. Even if you don't have your own livestock, producing a ready supply of manure, most farmers use it on their fields. Applying manure to your fields is part of maintaining good soil fertility because it contains nutrients, builds organic matter, and inoculates the soil with biology. This is one component of a typical sustainable soil management practice, but when farmers try to use manure alone, in place of fertilizers and soil amendments, growing goals and expectations are not met. The primary reason for this disappointment is that manure doesn’t provide all that your soil needs to produce nutrient dense crops. Additionally, using manure can increase weed pressure and contain unwanted residues.
First let’s look at the typical macro nutritional composition of various manure sources. These are identified in Table 1.
The macronutrient values shown in Table 1 are averages. It is important that farmers know the levels of NPK in their manure, so that proper application rates are used. When determining manure application rates, Phosphorous is the limiting factor. You can apply as much manure as needed to meet P requirements, but that will always leave a deficiency in Nitrogen and at times Potassium. Because of this Fertrell makes recommendations that balance these macronutrients and include the micronutrients needed to produce healthy crops. We generate our recommendations based on the results of your soil tests, nutrient value of the manure you are applying, and the needs of the crop being grown. This keeps your soil balanced and healthy, in a way that meets your immediate growing needs and promotes long term soil fertility.
But let’s presume that a farmer does not heed that recommendation and applies more manure, enough to supply all the Nitrogen their crops need, planning to work the manure into the soil and figuring that “more is better” so some extra P won’t matter. Eventually the soil will be so high in Phosphorous that it will tie up other nutrients and they will not be available to plants. The resolution for this issue is that no more manure can be applied, the farmer will need to meet nutritional needs by applying fertilizers that do not contain Phosphorous, until the P is used up and returned to a normal level.
The second drawback of the overuse of manure is increased weed pressure. This issue is a byproduct of unbalanced soil nutrition, which promotes the growth of weed seeds already in the soil. Additionally, many manures contain weed seeds from bedding materials. The increase in weeds is especially troublesome for organic growers and by closely monitoring the application of manure these weed problems can be minimized.
The final issue, unwanted residues, is a problem for farmers who purchase manure. When manure is not generated on your own farm it is difficult to determine what sorts of unwanted residues it contains. The three problem contaminants we most often see are herbicides, pesticides, and disease organisms. Herbicides and pesticides are harmful to soil bacteria and microorganisms, which decreases soil health. Diseases are especially concerning because they can have devastating effects on crops and long term soil health. When buying manure in, you need to be sure of its source and that it doesn’t include these unwanted contaminants before applying.
There are three key benefits of combining the use of manure with a complete fertility program.
Keeping your soil nutrients balanced, so they are available, can be used by your crops, and do not leach away or bind up chemically in the soil.
Producing more valuable, nutrient dense crops—for both animals and people.
Building nutritional reserves in your soil.
In this article, we have already discussed the first and most immediately detectable advantage—keeping your soil nutrients balanced. The second and third benefits take longer to notice, but are an extremely important part of developing sustainable farming practices
Let’s look at the second benefit—producing more valuable, nutrient dense crops. If you have heard Jeff Mattocks speak, then you have heard him say it is less expensive to feed your soil and grow nutrient dense forages than it is to supplement your animal feeds with minerals. It’s kind of a pay now or pay more later concept—and we believe you should invest in the health of your soil up front, by using a complete fertility program.
The third benefit—building nutritional reserves in your soil—is a very important, long-term benefit of using a complete fertility program. The dream of a farmer is to have fertile soil that has not been “used up” over the years. It doesn't have to be a dream; it can be a reality with this balanced approach and sustainable practices.
So, throughout this article I keep mentioning a “complete fertility program”, at Fertrell, that’s what we believe in and recommend. By using our standard blend fertilizers, our ability to custom blend fertilizers, and our component soil amendments—you can take a balanced approach to your farm’s fertility needs. If you are ready to implement sustainable farming practices, that will lead to your success, contact us to help you get started today.
