Many soil samples are taken in the fall and, according to extension agronomist Daniel Smith, this is a good time to collect this information.
“For soil sampling, it’s a really exciting time of year,” Smith said during a video from the University of Wisconsin-Madison Nutrient and Pest Management Program. “We want to measure how many nutrients are left in the soil, because that’s our savings account for the next crop to grow.”
Smith recommended testing phosphorus, potassium, soil organic matter and pH levels. “That way we can distribute the nutrients for next year’s crop via manure spreading now or in the spring and then we can think about buying the fertilizer to supplement those nutrients,” he explained. .
A sampling plan should be created by looking at a map of the farm and determining what crops will be grown and where. Smith said collecting one sample per 5 acres is the general norm, but many people will take more samples than that, working with 2.5 or 1 acre grids.
“Soil samples take such a small amount of soil from the landscape and are used to base our recommendations on next year’s profit and success,” Smith recalled, “so we need to be as accurate as possible.”
He said that the sampling depth is important. The proper depth is based on tillage or conservation system, but he said in Wisconsin, 6 inches is usually enough for most farms.
Smith noted that farms should also think about timely manure applications in the fall. He said to apply manure when soils are not prone to compaction or loss of environmental nutrients.
In summary, he reiterated the value of filling that savings account from the ground up and having a plan to do so.
“Stick to this plan, or just make minor adjustments, is really important for success,” he noted.