It's been an odd year. While some areas of the Cotton Belt have begged for rainfall, others have seen continuous drenching rains for the better part of the season. Still other areas have received just enough rainfall for growers' early maturing dryland crops to out yield their more costly, neighboring irrigated fields.
In those instances where Mother Nature consistently supplies your fields with more than adequate moisture, spending money on irrigation may seem foolish. Jim Thomas, agricultural engineer at Mississippi State University in Starkville, Miss., would like to change that mindset.
“Just because you didn't use a pivot this year, or you rolled out pipe that you may not have really needed, doesn't mean you won't need it next year,” he says. “Irrigation equipment should be treated the same way you would a piece of equipment like a tractor, or a management tool like a pesticide. This is one of the downsides of irrigation in the Southeast.”
There are times, he says, that you will need irrigation equipment, and other times where it may not be quite so necessary. Now, though, is not the time to give up on irrigation altogether.
“It's been a very unusual summer as far as rain patterns, but there will be a year, and it will probably be next year that you will need irrigation capabilities,” says Thomas. What's more, he says, irrigating provides benefits such as the ability to reduce herbicide treatments, because properly watered plants often canopy quicker and herbicides work better becasue of the actively growing weeds.
On the other hand, irrigation is not a substitute for poor management, he says. Often if there is a management problem, irrigation intensifies instead of solves the problem. High-level management is needed to make an irrigation system successful, because accurate decisions of timing and irrigation amount often determine whether a system succeeds or fails.
The most important determining factor for success, Thomas says, is timely application. “A producer must use the irrigation system when it is needed, and not when it is convenient. Starting irrigation too late to benefit the whole field, not putting on enough water, or stopping an irrigation application too soon can decrease yield and cause more problems than no water at all.”
For those growers who do have the capability to irrigate, but whose systems may have seen little use in 2003, Thomas recommends taking a little extra time for maintenance before closing up shop for the season.
“It won't necessarily hurt center pivots to sit there unused, because whether they are running, or it is raining, they are sitting in water either way,” he says. “That doesn't mean, though, that something couldn't go awry with the system during that time. Whether an irrigation system has been used, or not, growers should spend a little time on general maintenance each year.”
He suggests performing an overall check of the pivot, checking for loose wires, greasing components, inspecting gear boxes, cleaning panel connections, and checking pressure gauges. It's also generally recommended that you move the center pivot somewhat to make sure it is in working order, and check the tires.
Other maintenance activity that growers may need to do is check nozzle sizes. “It's something that should be done every six to eight years, but probably something most people never do,” Thomas says.
In the Delta because of the high iron content in the water, the nozzle holes on many of the older, low-impact sprinklers or apray nozzles can actually close up instead of wearing out larger. The good news is that most of the nozzle holes are a drill bit size, and if you've got a good drill set you can use those drill bits to check hole size. If you find problems, you may need to clean them out, or consider purchasing a new nozzle system.
A little time spent on general maintenance this fall could save you aggravation and time next spring. “Most growers will wait to perform routing maintenance until next summer when they need to begin using their center pivot systems. But if you can find something wrong with it now, you've got all winter to get it fixed. Otherwise, a problem next spring may put you behind two weeks, at a time when your crop is most in need of water,” Thomas says. “Any maintenance done today, will put you dollars ahead tomorrow.”
For those producers considering purchasing a center pivot system, Thomas says both the hydraulic and electric systems have their pluses and minuses. There are a lot of options available today, such as computer operating panels, different tire sizes, various nozzle packages and whether or not to put drops on the system.