With crop fertility costs increasing, pork producers can improve their bottom line by sampling manure to confirm its nutrient levels, says Tom Miller, extension swine specialist for Iowa State University.

As commercial fertilizer prices have skyrocketed the last several years, producers have responded by using more and more hog manure as the main source of fertilizer for their crops.

But many of those producers are basing manure application rates on book values that were established 5-12 years ago, Miller comments.

“This data was accurate for the time period which it represents, but with modern ration formulation many producers are including synthetic amino acids for balancing protein needs of growing swine. Phytase is also being used to reduce phosphorus excretion. The net result of these practices is that manure isn’t what it used to be,” he stresses.

Miller says the most accurate way to measure nutrients in manure is to sample it as it’s stirred and hauled. Iowa State University has a publication to help producers determine application rates based on nutrient content at www.extension.iastate.edu/Publications/PM1558.pdf.

Producers should sample and analyze manure each year and compare the findings with the previous year’s results to gain a more accurate picture of the pit’s analysis.

To sample a pit ahead of pumping for potash and nitrogen levels, a bucket dip test works fairly well. To sample for phosphorus, use a sampling probe as this nutrient tends to mostly be found in the heavy sludge in the bottom of the pit, Miller says.