Critical production factors for Southern Plains cotton growers, in order of importance, are: water, water and water. Following that trio, come the usual suspects of insect and pest control, proper fertility, variety selection, favorable weather, a bit of luck, and maybe a little more water.
Farmers who have planted more than a decade's worth of cotton also understand that the resource is far from unlimited. Most can tell a significant difference in the quantity and quality of irrigation water available now compared to just 10, in some cases five, years ago. They're looking for better ways to water their crops.
Edward Fisher, Sudan, Texas, says conserving water is not so much an issue as using what's available as efficiently as possible. Like most producers, he waters cotton all summer.
He's counting on subsurface drip irrigation to stretch a shrinking water supply as far as possible. He has had one field in drip for two years and plans to add another 90 acres next year.
“I watered all season,” Fisher told a group of Stoneville Seed Company representatives and media during a recent West Texas cotton tour. “We applied about one and a half inches per week. And with drip, we can spoon feed every acre every day.”
Crop consultant Dennis Flowers, says drip irrigation will make as much as 400 pounds more lint per acre than cotton grown under a center pivot or LEPA irrigation system. “We made 800 pounds more with drip last year,” he says.
“But we have to manage it more aggressively. We want a variety with a high yield potential.”
Fisher says the fields selected for drip installation also “have better yield potential.”
He likes the flexibility of the system. “We can irrigate in two cycles per day. The field is divided into three zones and each zone is watered twice a day.”
Irrigation tape is buried 12 inches deep, on 80 inch row spacings. Emitters are 24 inches apart.
“I put all my fertilizer on each side of the irrigation tape,” Fisher says. “I put no fertilizer on the rows without tape. The roots go to the tape, so I put fertilizer where the roots will pick it up.”
They put a 40-55-20 fertilizer on April 29. “But we added another 120 units of nitrogen through the system during the growing season. Total nitrogen was about 150 pounds per acre. We had to use a growth regulator to manage vegetation.
“We started with Pix at pinhead square and put on a total of 26 ounces.”
Joe Pate, with Diversified Sub-Surface Irrigation, Inc., installed the system and says proper design and installation is critical to long-term efficiency.
“We need uniform rows, so we use a topographical map and a GPS system to design a layout. We design the system to collect rainfall and to consider field contours and slope.
“The GPS and computer program take the guesswork out of the design. This is a big investment and we want it to be efficient and durable.”
Pate says new technology provides tape that will last up to 20 years. “We know of systems that have lasted longer,” he says. “The materials used now are much better than early products.”
He says maintenance will increase system life expectancy. “We recommend frequent monitoring, especially of filtration systems and an annual flush with sulphuric acid.”
Pate says yield advantage with drip averages about 400 pounds of lint per acre per year.
“With that increase, payback should be within five years. We know of farmers who have paid off their initial investment with two or three crops.”
Pate says interest in drip irrigation has “increased significantly in the Texas Southern Plains.”
“We've put in 20,000 acres so far and we've just scratched the surface. We can't predict what will happen to the aquifer. No one knows how fast it's depleting. But with drip irrigation, we prolong the life of it.
“This is the best use of water, nearly 100 percent efficient.”