You can cut down on fertilizer costs by knowing what the soil nutrient level is in the fields. Charlie Wortmann is a University of Nebraska soil fertility specialist. He recommends soil testing once every four years.
There are many ways to go about this process, but for the best accuracy, the samples should be representative of fields or areas within fields that are no larger than 40-acres. One sample of soil should be taken from each of 12 points.
Wortmann says, “Often you do that through management zone.” “You recognize that different soils, management histories, or yields exist, so you can look at different areas of the field differently to determine if they require different management.”
In maybe once every ten years, do grid soil sampling where one sample is taken every two-to-two-and-a-half-acres. Because it’s more intensive, the results can be put into spatial information tools like GIS to create a map of nutrient availability across the field.
Wortmann states that soil testing should determine at minimum five important properties.
“First, we want to examine pH and organic matter. Definitely phosphorous, potassium and zinc. These are the five most critical properties for Nebraska, he states. “And, of course you can test for other nutrients and other properties, but that’s sort of our basic package.”
Fall is a good time to sample soil. This allows for more time to receive results from the laboratory and can be used to design the fertilizer management program next year.
Source: Successful Farming