Testing, Calibrating Essential for Nutrient Management

Although harvesting likely is uppermost in producers’ thoughts this fall, they should keep in mind that soil testing, testing manure for nutrients and calibrating their manure spreader are vital for a successful nutrient management plan.

“Soil tests, manure tests and manure spreader calibration are three essential management practices that allow producers to meet crop yield goals by effectively managing manure,” says Chris Augustin, area nutrient management specialist at North Dakota State University’s Carrington Research Extension Center.

“Sampling and testing manure within a week of an application is very important to achieve accurate results,” he adds. “However, results are only as good as the sample taken.”

Sampling solid manure involves taking about a dozen samples with a shovel from various locations in a pile and mixing those samples together in a plastic 5-gallon bucket. A composite sample then can be collected from the bucket and placed in a plastic container from a testing lab.

Labs that will conduct such tests include the NDSU Soil Testing Laboratory, (701) 231-8942; AGVISE Laboratories, (701) 587-6013; and DHIA Laboratories, (800) 369-2697.

Fill the plastic container about three-quarters full to provide room for air and expansion. Label the bottle, place it in a plastic bag, fill out all the information on the form from the testing laboratory and mail the sample.

Liquid manure should be agitated for two to four hours before sampling. Collect about six samples by dipping into the manure container and pouring the liquid into a plastic 5-gallon bucket. The samples should be mixed and transferred into a plastic sampling bottle from a manure testing lab. As with solid manure samples, leave some space in the bottle.

Many labs recommend that after collecting the samples, they should be frozen or packed in ice and sent in a cooler. This prevents the samples’ chemical and biological properties from changing.

Labs also recommend sending samples early in the week to avoid weekend layovers and problems with maintaining sample integrity.

Labs can test for many nutrients, but the minimum testing should be for total nitrogen, phosphorus and potassium, Augustin says. Testing manure for inorganic and organic nitrogen can lessen the guesswork that goes into making sure nutrients are available for crops.

If producers need assistance in calibrating their manure spreader, a new NDSU Extension Service publication can help. “Manure Spreader Calibration for Nutrient Management Planning” (NM-1418) is available at county Extension offices or online at http://www.ndsu.edu/uploads/media/NM-1418_proof_2.pdf.

For more information on nutrient management, contact Augustin at (701) 652-2951 or chris.augustin@ndsu.edu, or visit the NDSU Nutrient Management Web site at http://www.ndsu.edu/nm.

NDSU Agriculture Communication