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Sampling Manure for Nutrient ManagementManure as a Resource SeriesSampling Manure for Nutrient ManagementNutrients required for optimum crop production can be supplied by several sources including manure, commercial fertilizer, or a combination of the two. Regardless of the source, nutrients must be applied in the right amount and at the right time to meet the crop needs and producer objectives while preventing surface and ground water contamination. By determining the nutrient content of manure sources, producers can adjust the amount of commercial fertilizer needed to meet crop requirements. With the cost of commercial fertilizers steadily increasing, the use of manure as a nutrient source reduces inputs to crop production. Producers have two options for determining the nutrient content of manure produced on their farm:
Estimated values found in published databases are averages from samples collected and tested over a period of years from a wide variety of locations. Estimated values, therefore, have the potential for wide variation when compared to actual nutrient values on site. A laboratory analysis is the preferred and most accurate of the two methods. An analysis measures the nutrient concentration in manure produced on a specific site. In Montana, permitted facilities are required to obtain manure analysis annually whenever manures will be applied. Estimated Nutrient Content of ManureNutrient content of manure varies significantly with species, age, and weight of livestock; feed program; and manure handling and storage. To compound matters, nutrient content is also affected by climatic conditions, application methods, and timing of incorporation. Minimally, manure should be tested for total nitrogen, inorganic nitrogen, total phosphorus, total potassium, and percent moisture. An analysis of these nutrients provides the necessary data required to develop a nutrient management plan.
The information in the tables above is adopted from MontGuide 8704 “Soil Testing, Procedures, Interpretation, and Fertilizer Sources,” Montana State University Extension Service, 1996. Sampling Manure for Nutrient ManagementThe accuracy of a laboratory analysis depends on the quality of the manure sample received. A solid manure sample collected as close to the time of land application as possible provides the best information about its fertility value. It is important, however, to allow the lab enough time to complete the analysis and return the results. Usually three weeks is sufficient. Liquid manure must be agitated before sampling and is usually applied to land after the sample is taken. Therefore, it is suggested that producers handling liquid manure use the average of several years of nutrient test results to estimate the nutrient level in the manure. When information from past years is not available, NRCS professionals can provide and estimate of nutrient levels using the manure management planner (MMP) software. Sampling Solid ManureAn accurate lab analysis of solid manure hinges on collecting a representative sample.
Sampling Liquid ManureSampling from a loading pipe or tank spreader is the preferred method of collecting a liquid manure sample.
Sample Identification and Shipping
The lab operating in Montana is: Energy Laboratories A “chain of custody” form for submitting samples is also available on the Energy Laboratories website. For More InformationFor information or assistance with management options contact your local Natural Resources Conservation Service (NRCS) or conservation district office. Natural Resources Conservation Service Montana Assoc. of Conservation Districts For information or assistance with regulatory requirements of manure management, contact the Montana Department of Environmental Quality. Department of Environmental Quality Manure as a Resource SeriesThree additional brochures are in this series. To receive a copy of any of the following brochures, visit your local NRCS office.
If you encounter any problems with the file provided on this page, please contact Technical Resources at 406-587-6822. This document requires
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