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Serving: Central

Improve prospects with crop irrigation

2000 drouth has Mid-South farmers making plans for water Mid-South farmers are longing for just one good pitch to knock out of the park, but Mother Nature hasn't put one over the plate in three years.

Last year was the perfect example of what can happen when Mother Nature throws a curve ball instead of the perfect pitch, a growing season of timely rains and ample sunshine. Day-after-day of triple-digit temperatures and distant memories of that wet stuff fondly remembered as rain had farmers scrambling for some relief from the dry, scorching weather.

As a result, many growers with plans to hit a grand slam in 2001, with or without Mother Nature's help, are gearing up to provide their crops with some artificial rain this coming growing season.

Whether you are irrigating the crops on your farm for the first time or the 50th time, it pays to begin planning now to succeed next summer. That means considering drainage, land grade and subsoiling practices months before the water flows out of the well into your field.

Jim Thomas, irrigation specialist and agricultural engineer at Mississippi State University in Starkville, Miss., says good field drainage can help you plant earlier and harvest more efficiently.

"It lets you farm 100 percent of a field instead of 50 percent at a time," he says. "When you have good drainage, your field operation efficiency is better and more timely because you are not trying to go around the wet spots."

Your goal, he says, is to shoot for grades steep enough and ditches clean enough to drain the water off your fields in 24 hours or less. "Good drainage is a requirement, not an option. If you don't have it, you're going to have problems."

In addition, Thomas recommends cleaning out both your ditches and your neighbors' ditches. Otherwise, he says, your neighbor's water will back up into your field, despite the work you've done on your field.

Land grades "A water furrow plow is good for throwing dirt clods or having water fights. It's also fine for digging ditches, but I think we've got better equipment available to level our fields," Thomas says. "We've got better agricultural leveling equipment than what is used to build highways. Despite this fact, we send a laborer to the field on a water furrow plow and hope he hits the low spots."

In the Mid-South, land-leveled fields generally vary from a zero grade slope to 0.2 percent grade slope.

The controversial zero grade slope, which offers little in the ways of drainage, is considered acceptable by Thomas for use in continuous rice fields. However, he says, the use of a zero grade field is marginal for soybeans and is not considered acceptable for cotton or corn fields.

In a zero grade system, ditches around the field act as a French drain and, even with water furrows, field drainage is slow. "What will we do with this system in a wet spring and a wet fall?" Thomas asks. "I'm not thoroughly sold on it yet, but there may be places where it will work."

A land grade slope of 0.05 percent is considered ideal for rice on heavy soils or soybeans planted on beds, but not for corn or cotton. In comparison, a grade of 0.1 percent can be used for rice and soybeans, or cotton and corn planted on beds. A 0.15 percent graded field is routinely used in the Delta for rice, soybeans, corn and cotton. However, when a land-leveled field moves to a grade of 0.2 percent, rice becomes questionable because rice levees begin to stack up at that slope level, although soybeans, corn and cotton, planted in rows, continue to do well, according to Thomas."

Thomas considers 0.15 the ideal slope grade for most Delta farms because, he says, "With the current farm bill you've got four crops to consider. You're going to plant what will pay the best in any given year."

Subsoiling Whether or not you chose to make subsoiling a part of your irrigation system will likely depend on your soil type.

According to Thomas, those Delta farmers planting on Sharkey clay soils in either a dryland or an early planting production system may want to consider subsoiling once every three years.

For subsoiling Sharkey clay soils, Thomas recommends subsoiling in the fall. "Fall subsoiling should be followed by at least one disking to break it back down a bit. Even then, it is going to be a little soft in the spring," he says.

Although subsoiling Sharkey clay soils generally equate to about irrigation application, it's primarily recommended only for dryland systems. "We don't use it as a practice in conjunction with irrigation. We use it as a practice in lieu of irrigation," Thomas says.

"Subsoiling works when you get normal-to-good rainfall. It doesn't work as well in dry years like last year," he adds.

For those farmers farming Tunica clay soils, which are about 30 to 40 inches of clay over sand, Thomas suggests subsoiling once every three years. Again, he encourages growers to subsoil in the fall and follow with a disking operation.

"Subsoiling Tunica Clay soils almost equates to an irrigation production regime. However, this is not something you want to do if you are going into rice next year," he says.

For ideal cotton-type soils, Thomas recommends subsoiling every one to three years to supplement irrigation efforts.

"Those are the soils we have trouble getting water into because they have very little organic matter," he says. "Subsoiling cotton soils equates to about one irrigation application in most years. It can be used either for early dryland planting or in conjunction with irrigation."

When it comes to irrigating Mid-South crops, even the most well-intentioned farmers sometimes start irrigating a little later than is optimum, or with a little less water than the plant is thirsting for.

The time to remedy that "too little, too late" problem is now. It's not too early to begin doing some preventive maintenance on your irrigation systems, according to Jim Thomas, irrigation specialist and agricultural engineer at Mississippi State University in Starkville, Miss.

Without winter maintenance, Thomas says, "Your center pivot will run fine as long as you watch it this spring, but as soon as you drive away, that system is going to quit."

Thomas offers the following winter maintenance and spring planning tips.

- Pull all irrigation engines that can be moved from the field into the shop to perform routine, annual maintenance. Consult your owner manuals on all of your irrigation equipment for recommended winterization and routine maintenance.

- Check the oil in all gearboxes. Also, drain any gearboxes to make sure you don't have any water in them. If water is allowed to remain in a gearbox, there is a great likelihood it may freeze, causing damage to your equipment.

- If you use gated pipe, replace broken gates and clean the gaskets.

- If you are running roll-out pipe in your irrigation system and are using gates, clean the gates out in a weak acid solution to get rid of any iron buildup.

- For center pivot systems, check for worn and broken sprinklers and fix or replace them. Also, check U-joints, gear boxes, seals and wiring for any visible damage. Check the truss systems to make sure bolts are tight.

- Check the condition of tires on center pivots to be sure they aren't rotting. Look at rubber boots on the towers between the joints to make sure they are not cracking.

- Grease all fittings on pivots, power units and wells to keep them from getting rusty and getting water in them.

- Close and seal any electrical panels on electric wells or pivots so rodents and birds can't nest in them. Cover the electrical panels and make sure the seals are good and tight on any wires running into the units so there are no holes for critters to get in.

- Check the insulation on all the wiring coming in to the electric motor on a pivot or well. Also, Check the integrity of all wires and make sure the insulation is not cracked or flaking off.

- If you have power units left out in fields, and they are water-cooled, make sure they have antifreeze in them. Otherwise, they could freeze and crack, causing unnecessary damage.

- If you had problems with water or problems caused by irrigation, now is the time to pull samples and check wells for water quality.

- Order or book any needed irrigation equipment, such as roll out pipe, for the upcoming crop season.

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