As crops come off the fields and farmers prepare for winter, it is a time to make decisions that will impact both productivity and finances for the next growing season.

“We are in an environment with historically high fertilizer prices. They have come down a little bit, but there are still some challenges out there in terms of efficiency,” said Damon Smith, an extension field crops pathologist with the University of Wisconsin-Madison. During a “Bumper Crops Series” video, he asked his colleague Kevin Shelley what farmers could do to mitigate these expenses.

“One of the main practices we want to be sure we are up to date on is soil testing,” said Shelley, an outreach educator with the University of Wisconsin’s Nutrient and Pest Management Program.

“Also, take soil samples at the recommended density,” he continued, which is one sample every 5 acres. “That can help to inventory the background level of nutrients in each field and across the farm, which will allow us to better match our fertilizer purchases, manure use, and the crops we plan to grow,” he explained.

Shelley said it is common to see quite a bit of variability in terms of soil fertility across the farm. “Soil testing can help us identify that and help us decide how to prioritize and allocate our nutrient resources in the most economically efficient way,” he pointed out.

Fall is a good time to sample, he said, because then that information can be reviewed and utilized over the winter. There can be some variation in results between spring and fall tests, but Shelley said the differences are marginal. In general, “Anytime is a good time to test,” he stated. “The main thing is to take the tests and have a current set of test results to use.”

Shelley shared that the general guideline is to test at least once every four years, and once every three years is better. He said it also depends on the fertility level of the soil. If a particular field is low in a certain nutrient, testing more often may be more beneficial to track progress.

Shelley’s take-home message was that soil testing plays a valuable role in maximizing crop production, and Smith summarized the conversation in three simple words: “Test, test, test.”

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October 17, 2022
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