BMP’s and Manure

Livestock manure is rich in plant available nutrients that are valuable to crop producers. Approximately 2 billion tons of manure are produced each year. Managing livestock manure has become an increasing concern for both livestock and crop producers and the general public. Large volumes of manure are produced in areas with concentrated livestock operations. These facilities need an increasing number of acres to apply the manure over. Now it is up to Agricultural consultants and Agronomists to help crop producers manage manure applications on their land.

The first step in any nutrient management plan is to develop a routine soil testing program. The second step is to test any manure that will be applied for nutrient content. AGVISE Laboratories can provide both of these services. University research has established information on the average nutrient content of many types of manure. These averages can be helpful, but in today’s precision agriculture, these average figures are not good enough. Would you buy or sell commercial fertilizer without knowing what the analysis is? I don’t think so! The nutrient composition of manure varies widely due to moisture percentage, type of bedding, type of livestock, age of livestock and feed rations.

Without a manure analysis, producers may over or under apply nutrients needed for crop production. Obtaining a representative manure sample is just as important as getting a representative soil sample. A few hints on sampling various manure storage areas are listed below:

Solid Storage System: A representative sample must include many sub samples collected from throughout the pile or area and combined into one bulk sample. Mix the bulk sample well and submit one composite sub-sample for analysis (1/2 to 1 quart). It may be necessary to submit more than one sample for analysis if the manure in the storage area varies greatly in the amount of time it has been stored.

Liquid Systems: For liquid systems, the manure must be agitated before sampling. Collect several samples and combine into one bulk sample. Mix the bulk sample and then fill the sample container provided by the laboratory (1/2 to 1 quart). After collecting the sample, keep it refrigerated or frozen if not sent to the laboratory that day. When shipping the sample, be sure to place the sample container in a tightly sealed plastic bag to insure against any leaking. Please remember to ship early in the week so the samples will arrive at the laboratory without delays.

Once test results are received from the laboratory, a nutrient management plan needs to be completed based on soil and manure analysis. Determining the crop nutrient needs involves accounting for the nutrient inputs from the manure and the nutrients in the soil, while adding the remaining nutrients with commercial fertilizer. Following “Best Management Practices”, put these principles to work. In some states, such as South Dakota and Wisconsin, growers are now required by law to have a best management plan in place before applying manure to their fields. You may want to check with your local or regional agencies for any special requirements in manure application.

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Whether required by law or not, all nutrient management plans should calculate the value of the manure on a basis of plant nutrients supplied. Keep in mind that there are substantial losses of nitrogen if the manure is not incorporated after application. Even in cases where the manure is injected with sweeps or knives, there can be a loss of 5 to 15 percent (see table). Nitrogen availability also varies greatly depending on application, while phosphorus and potassium are not as dependent on application method. Losses from runoff are always a danger if the manure is not incorporated after broadcasting.

The bottom line is public concerns and new regulations have changed the way in which we must view animal manure management. This so called waste is actually a valuable resource waiting to be managed. Proper use of manure will provide more profit for producers, improve soil properties and protect the environment.