Conquering some of the challenges cotton producers face to raise this year's crop may take some different management techniques says a Texas Cooperative Extension specialist.
“Our major problem right now is dry soil,” says Leon New, Extension irrigation specialist in Amarillo. “We normally have a full soil profile at this time. This year we have none.”
The good news is gas prices are going down, he says. That could help make pre-plant irrigation more affordable, which will begin to build up soil moisture depleted through the drought.
Cotton is planted around May 10 to May 15, New says. That only gives a producer about six weeks to get the soil profile full before the crop starts to use it faster than it can typically be applied in the July heat.
Producers can't wait until then to start planning water for the crop because of irrigation limitations, New says. A total of 6 inches of soil moisture from irrigation, rain or a combination of the two, needs to be present by the end of June or the crop will stress during the peak growing season.
“Management is going to be key in getting water to the crop,” he says. “I don't know that we have a choice of not pre-watering this year. I think good subsoil water is essential and we don't know when it's going to rain.”
When a center pivot irrigation system applies 3 gallons per minute per acre or less, it takes a week to put on 1 inch of water, he says. If the well is pumping 3.5 gallons per minute, that's 1.25 inches per week.
“I would put a little subsurface water down,” New says, “especially if you can get the pumping cost down.”
A producer south of Amarillo, at $8 per mcf of natural gas, will spend $6 per acre-inch of water. North of Amarillo, where the water is deeper, the price will be $8 per acre-inch, he says. That will produce enough cotton to make it affordable if the producer stays ahead on watering.
Starting with a 2-inch pre-water will mean having to irrigate with only 4 inches in June, or less than that if the rain comes, New says.
“Then, what we have to look at is production per acre inch of water.”
Production typically is around 85 pounds per acre-inch of irrigation water and it needs to be 100 pounds or more per acre-inch of irrigation water, or 70 pounds per acre-inch from irrigation, rainfall and soil moisture all considered.
“We have the management, technology and varieties to make these numbers go up,” New says.
“This year I would wait through March and April and see what rain we get and then I'd put on a couple inches of irrigation,” he says. “You just can't get behind because by July, you don't have enough irrigation capacity to stay up with the needs of the crop.”
Utilizing the Texas High Plains Precipitation Evapo-transpiration network can help producers best determine where they need to be with their watering program, he says. The network can be accessed at: http://txhighplainset.tamu.edu
Because there's no moisture to spare, this year it is even more critical for producers to consider using low-energy, precision application irrigation systems with drag hoses or bubblers, he says.
With these two methods, New says, the producer generally gets 95 percent of the water applied to the crop. The low-elevation spray application irrigation will lose up to 25 percent more water through evaporation when used in low-profile open cotton, he says.
“The less available irrigation we have, the more efficient we have to be in getting it to the crop,” he says. “You don't have any water to lose.”
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