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A truck-mounted horizontal spreader applies manure to a field at the NDSU Carrington Research Extension Center.
Photo Credit:
Mary Keena
Title

Manure as a Fertilizer

Authored on
Mar 07, 2022
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Using manure as a fertilizer has become a recurring thought during this long, cold winter. With the continuous rise of fertilizer prices and prolonged supply chain issues, the bedded-pack beef manure that is commonly thought of as a waste is ready to work. Nutrients such as nitrogen, phosphorus, potassium and sulfur, to name a few, are present in manure and available at various rates for plant growth. Besides the bump in fertility, there are other benefits to using manure in your cropping system. Manure has been shown to increase water holding capacity and bulk density along with improving biological properties of the soil.

Manure has many positive attributes, but it also has some drawbacks. One of the drawbacks is lack of uniformity and another is the issue of weed seed management. While it is true that manure does contain viable weed seeds, it is also true that manure contains the nutrients necessary to nourish the weed seed bank that already exists in your soil. Nonetheless, there is a practice that can help alleviate both of these problems at the same time.

Composting is the process of piling and mixing moistened manure to encourage thermophilic decomposition. The heat that is created during the composting process has the ability to kill weed seeds, pathogens and parasites all while creating a uniformly mixed product with alike surface area. Composting manure also changes the availability of nitrogen for plant use, turning it into a slower release product. The nitrogen in fresh beef manure is approximately 50% available for plant growth during the first growing season after application, whereas the nitrogen in composted beef manure is only 15-20% available. Most often, fresh manure is used as a nitrogen fertilizer while composted manure is used as a phosphorus fertilizer because phosphorus is approximately 80% available in both products. It is important to know which you are dealing with.  

Sampling manure and compost is the most accurate way to know the nutrient content (amount, not availability). NSDU Extension publication NM1259, “Solid Manure Sampling for Nutrient Management Planning” gives step-by-step instructions on how to sample and an explanation of the results.

Similar to when using commercial fertilizer products, calibration becomes important when spreading manure or compost. By knowing the amount of nutrients present in the product and the rate (tons/acre) that it was applied, you can calculate the amount (pounds/acre) of nutrients that were applied and how much will be available for plant growth during the 2022 growing season. You can learn more about calibrating manure spreaders in NDSU Extension publication NM1418, “Manure Spreader Calibration For Nutrient Management Planning”.

Numbers from the National Agricultural Statistics Services indicate that in 2019 there were approximately 55 million pounds of beef manure produced in North Dakota. Manure contains useful nutrients that are an effective fertilizer and can improve soil health. For more information about using manure as a fertilizer, contact your local NDSU Extension agent at https://www.ndsu.edu/agriculture/ag-home/directory.

Mary Keena
Extension Livestock Environmental Management Specialist
Mary.Keena@ndsu.edu