By Clint Thompson
Farmers need to take soil samples now to ensure essential nutrient levels in their fields. A lack of the right amount of a specific nutrient could cost growers who want to maximize their yields, according to Audrey Gamble, assistant professor and Extension specialist at Auburn University.
She said soil testing is one of the easiest ways for producers to know what levels are for nutrients like phosphorus, potassium, calcium and magnesium.
“We need to make sure we get good representative soil samples to represent what’s going on in our field and see where we’re deficient in certain nutrients, because any one nutrient that’s limiting can cause us a yield penalty,” Gamble said. “Using a soil test to make sure that we’ve got all those in sufficient range is going to help us maximize our return on investment in cotton and other row crop production systems.”
Gamble said soil sampling doesn’t test for nitrogen in the soil, but Extension provides recommendations for nitrogen based on crop and soil type.
“Those recommendations are based off years of research to show where we see the maximum response to nitrogen for a given crop,” Gamble said.
One of the most important benefits of sampling is understanding what the soil pH is in each field. If the soil pH is not right, it can limit the uptake of nutrients.
Farmers can sample their fields a couple of ways. They can divide their fields into zones, test 15 to 20 subsamples and mix one composite sample in each given zone. Growers can also grid-sample by dividing a field into 2.5-acre subplots. Samples are taken from each subplot.
“The more samples that we can take, the more accurate we can be with our nutrient recommendations, and the more precise we can be,” Gamble said.
Corn season is just a week or two away for some growers, and cotton season is just a couple of months away. The time to soil sample is now.
“Planting season is upon us, so we want to go ahead and get those soil samples. It’s been very wet right now, so as soon as we can get in the field, we need to be taking those samples so that we can make sure we get those nutrients out ahead of planting,” Gamble said.