With cotton prices dropping by more than 20 cents per pound since early December, producers are scrambling to cut out some inputs altogether and minimize those that are essential to producing a crop.
Whenever caught in such a price squeeze, most growers will begin to tinker with fertilizer applications. And, while there might be room for some adjustments, these shouldn't be made at the expense of yields.
In fact, cotton yields might possibly be increased by making last-minute adjustments such as applying finely ground lime, says Glen Harris, University of Georgia Extension soil scientist.
“We used to say there was nothing we could do if we found a pH problem around planting time, but we've had some success with using finely ground limestone,” says Harris.
Using ground lime isn't the best option, he adds, and it probably should be viewed as more of a “rescue” treatment for low pH areas. “I would prefer to catch pH problems with a fall soil sample and then apply lime in the fall or early winter. But if you discover that you have fairly large areas with a low pH, one-half ton of fine lime will bring up that level. Within 30 days, it'll bring the pH up to a level that'll prove beneficial,” he says.
It's important, says Harris, that growers know how low a pH level should be to justify such a treatment. “If you sample now and find that you have a pH level of 5.8 or 5.9, you might be able to get by. Our target level is 6.0. But, if you have an area that is a 5.5 or lower, this finely ground lime might be helpful.
“Within 30 days, that half ton of lime could bring a 5.5 up to a 6.0. If you catch the problem early enough, the cotton plant is still young and, hopefully, not too much damage has been done,” he says.
A half ton of finely ground lime should cost about the same as a full ton of regular lime, notes Harris. “It definitely would be worth the cost if the situation calls for it. Once the pH level gets down to the 5.5 range, we start getting aluminum toxicity, and lime is the only way to fix the problem. A low pH can reduce cotton yields by at least 50 percent,” he says.
Due to its increasing cost, nitrogen continues to be a popular topic of discussion among cotton producers, says Harris. “Everyone is trying to figure out how to get the most for their money, and many farmers are looking at different sources of nitrogen. There's nothing wrong with shopping around, but remember that all nitrogen is not created equal. It's good to compare products. But be careful if you decide to switch nitrogen products — know what you're buying.”
Some growers, he says, have stopped putting out nitrogen before planting, and that's not a good trend. “There are places to cut, but I hate to see growers not putting out nitrogen before or at least immediately after planting. If our phosphorus levels are in good shape, we might be able make adjustments there. But we need to be putting out nitrogen and potassium.
“Some growers aren't putting out anything at planting. In dryland situations, they're waiting to see if they get a stand before making the investment, but that's not recommended. The key is to put out nitrogen and potash at planting or soon after planting.”
Georgia's current nitrogen recommendations are based on yield goals, ranging from 750 to 1,500 pounds of lint per acre, says Harris. With nitrogen prices continuing to rise, there's every incentive this year to be conservative about nitrogen rates, he adds.
“Some growers may be shooting for 1,500 pounds per acre when they realistically should be shooting for 1,000 pounds per acre. It's not a big difference — maybe 15 to 30 pounds of nitrogen per acre — but it can add up quickly over a lot of acres. Match the rate with the need, and be realistic when setting yield goals.”
Harris cautions growers to beware of “snake oils” and other “miracle” treatments for cotton. “If it sounds too good to be true, it probably is. And, don't expect a miracle from a five-gallon jug. These are the two best things I can say about these miracle products.
“Some of these products might contain nutrients needed by the cotton plant, but there are other materials that will do a better job, and they're usually cheaper. You shouldn't be wasting your money, especially in a year like this one.”