Not long after you make that pass through the field with the combine, you will be making the rounds to collect soil samples. Dan Kaminsky, a certified crop adviser from Monroe, Ind., recommends going through this sampling process at least every other year.

“Let’s say you’re going to farm for 30 years,” Kaminsky says. “If you only sample every four years, you only have seven times to get a chart. And it takes three times to really start seeing where you’re headed. So, now you’re halfway through your career, and you’re still starting to get an idea of where you’re going. But if you sample every other year, you have twice as many data points.”

There also is a best way to sample, Kaminsky says. He shares that sampling by soil type will bring more accurate results than grid sampling by far.

“If you do a grid, you go to the center of that 2 1/2 acres and take samples, right?” Kaminsky says. “How do you know you’re not in three soil types? You just don’t know.”

Try GPS sampling

Rather, Kaminsky is a proponent of sampling by soil type. He has found that it gives him a more accurate look at what the soil needs and where exactly it needs it.

“One thing I have found over the years is that soil pH and lime rates really mirror soil-type maps,” Kaminsky says. “And I had some real problems with grids really directing lime applications to the right area.” Switching to sampling by soil type will allow you to break up the field into soil types with drastically varying needs rather than dividing it into a grid that disregards soil types.

He shares that he can overlay Natural Resources Conservation Service maps to break the field into different soil types, or he will drive through the field to get a feel for the topography before he pulls samples.

The NRCS maps may not always be accurate because they will lump small pockets of varying soil types in with the predominant soil type in that area, Kaminsky says. Most NRCS offices today also do not give out printed maps. One solution could be using Web Soil Survey to determine soil types in a field. However, Kaminsky shares that some producers may use their yield monitor data to draw maps that differentiate soil types.

Extra considerations

If you still prefer to grid sample, Kaminsky suggests breaking that field into 1-acre sections instead of 2.5-acre sections to ensure you get more accurate results.

“If I would do 1-acre grids, I think I would take a couple points in the field and do some intermediate samples just to see where I’m at in that area,” Kaminsky says. “You can pick up the predominant soil types and say, ‘OK, this area is part of that soil type. And this one over here.’ And I’m just going to go in there in between and take a couple samples to see if soil pH is heading down or up, to see where I’m going.”

Additionally, while fall is a popular time to gather soil samples, Kaminsky shares that spring could be a better time to sample. He says that spring sampling immediately following planting allows you to develop fertilizer and lime recommendations by the middle of summer. This frees up that quick turnaround time in the fall to figure out what you need to apply as you wait on soil test results. However, if you make the switch to spring sampling, you will want to stick with it to keep an accurate comparison from year to year.

Ultimately, Kaminsky says, the best way to sample is to find what works for you. What’s key is to ensure that you are sampling regularly.