Whether you’ve finished cotton harvest or have more acres to strip or pick, it’s not too early to schedule soil testing. And with fertilizer prices still near the top of input costs, soil fertility measurement may lower production costs without sacrificing yield or quality.
Crop specialists see continued benefits of soil testing about once a year to help determine nutrients in the ground and how much supplemental nitrogen, phosphorus or potassium is needed to generate peak cotton performance.
“We try to encourage growers to use this time of the year for soil testing,” says Ben McKnight, Texas A&M AgriLife Extension cotton specialist, College Station. “There’s a lot of good data across the Cotton Belt that illustrates how we can identify surplus nitrogen and use that data to credit that toward the next year’s N requirements.”
McKnight, who works with growers in central and southeastern Texas, notes those areas had average to above-average production.
“We caught good rain, which produced good yields, especially in dryland fields. Fiber also looks good,” he tells AgFax.
Growers in a corn-cotton rotation also had good corn yields.
“In those areas, the N demands for corn and cotton are likely quite different,” he says. “If producers are coming out of corn in a drier year with plans for cotton next year, they can be surprised at how much N is still in the soil. There may be an ample amount in the soil, meaning much lower N applications are needed, depending on goals for yield.”
Relief for Tight Budgets
The University of Arkansas Extension cotton enterprise budget shows little relief for input costs in 2026. But soil testing could identify ways to reduce costs.
For its furrow irrigated cotton budget, Arkansas Extension estimates these fertilizer-operating expenses: urea at about $77 per acre; phosphate at about $40 per acre; and potash at $22 per acre. That’s about $140 per acre, excluding application costs. If a soil test indicates there is an excess of any of these nutrients, costs can be cut substantially.
“With the way commodity prices are looking and other hardships faced by growers, we need to use every technology we have for grid soil sampling,” says Zachary Treadway, Arkansas Extension cotton agronomist, Newport. “Growers also need to use precision maps and other precision agriculture that can help save them a lot of money.”
Treadway says many Arkansas growers work with crop consultants.
“They have been pulling soil samples for the last few weeks,” he says. “Our soil types are across the board; more clay toward the Mississippi River, to sandier soil in cotton-peanut ground. Our growers are forward thinkers and depend heavily on their consultant/fertility guys.”
Soil types are just as varied in the regions covered by McKnight.
“In the Brazos Bottom, soils may range from clay in one area, then sandy loam a few miles up the road where they’re growing watermelons,” he says. As for P and K, he adds that “growers may have subsoil that may contain much potassium, but you never know until you do a soil test.”
He points out that for cotton, potassium has nearly an equivalent plant requirement as nitrogen for yield goals.
“Go ahead and get potassium and phosphorus applied in the fall or winter for better results,” McKnight says, noting that a deeper test-probe depth can add more information on soil nutrients.
“In most cases, you’re only going to be as productive as your limiting factor. We often just measure for the major nutrients. But we should also take micronutrient analysis every few years. Growers may have all the N, P and K they need, but by relieving any micronutrient deficiency, they can help limit yield loss.”
He recommends that, if possible, growers should use an 18-inch to 2-foot test probe to better analyze fields for major and micronutrients.
“This can help further identify soil nutrients,” he says. “If there’s deeper N that isn’t detected, producers can end up paying more for unneeded fertilizer, and more for Pix or defoliation due to extra plant growth in the end.”
Soil Health Indicators
The Noble Research Institute, Ardmore, Oklahoma, defines soil health as “the continued capacity of soil to function as a vital, living ecosystem that sustains plants, animals and humans.” It lists various soil health indicators that are typical of good-producing ground.
A crucial indicator is whether a field has “biologically active soils,” with the presence of earthworms, earthworm excrement, dung beetles or evidence of their activity. Earthworms create burrows through the soil profile, which enables water to move down and creates channels for roots. Noble scientists add that earthworm excrement helps increase nutrient cycling because, pound-for-pound, they contain significant amounts of nitrogen, phosphorus and potassium.
No-till and minimum-till production helps regenerate soils with more organic matter and compost. Better soil usually helps growers produce better yields and quality. Soil tests help growers gain better knowledge of their soil health.
