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Serving: Central

Variable rate irrigation

A late night phone call to Luray, S.C., farmer Bud Bowers usually means one of his 10 Valley irrigation pivots has shut down. A quick trip to his computer usually fixes the problem.

Bowers has each of his Valley irrigation pivots equipped with variable rate application and each system is set up to call his cell phone if the pivot shuts down.

“I saw a presentation at a Beltwide Cotton Conferences several years back on variable rate technology and it seemed to fit my farming operation perfectly.

“I have a number of different soil types across my farm and both variable rate irrigation and variable rate fertilization have been big cost savers,” he says.

Bowers is a third generation farmer — and a good one. His father sent him to college to study business, not agriculture. Armed with a degree in business from the University of South Carolina, he joined the family farming operation full time in 1976.

Though he spends long hours ‘hands-on’ farming, Bowers can control most of his farming operation from a computer setup in a small office in his home.

GPS-generated soil maps give him a virtual view of his farming operation and GPS-guided equipment make on-farm variable rate application possible on most of his fields.

Bowers farms about 1,500 acres of peanuts and row crops. With 600 acres under center pivot, he has a number of options for crop rotation, used primarily on his cotton and peanut land.

The Valley Irrigation system has software packages that would allow him to do a great deal more with his pivots.

“I have cotton, peanut and corn programs for which I can use variable rate, or I can run the irrigation pivot without the program. If we get a stretch of extremely dry weather, I use it with a straight rate of water,” Bowers says.

He can set the rate of irrigation water from .12 inch to 5 inches. The rate of water application is controlled by a solenoid. Standard setting is ½ inch of water.

“On a sandy spot in the field, the solenoids stay on and the full rate is applied. In heavier soils, with better moisture retention, these fields may get virtually no water.

“Water is a valuable commodity and there is too little of it. Variable rate irrigation allows us to be better stewards of this resource — it saves us money and it keeps regulatory agencies away from our farm, and that’s a good thing.”

On a hot early September afternoon, Bowers checked his cotton fields. Some had cotton bolls open and ready for defoliation. No need for water on this cotton. In another part of the same field, he programmed the pivot to skip the open areas and irrigate the areas that needed a little more water.

Soil probes, similar to a tensiometer, monitor soil moisture at 8, 16, and 24 inches. The computer program for the monitors tells him when he needs to irrigate.

Farmers generally want to look at data and interpret it to mean what they think it should mean, but with this system, the grower knows which parts of a field need water and which don’t. The technology driven by the software on these pivots allows a grower to do what needs to be done, not what he thinks needs to be done, Bowers says.

In a typical year, his variable rate irrigation system makes about an extra bale of cotton per acre.

“If dryland cotton produces two bales per acre, we expect to get three bales from our irrigated fields,” he says. “Some of that increase can be attributed to putting irrigation in fields with a higher yield potential.”

In addition to improving his crop yield, variable rate application saves a huge amount of water. Average savings range from12 percent to 16 percent, and up to 28 percent in cases where there has been severe over-use.

Like many farmers in the Southeast, Bowers also does custom production work for other farmers — in his case custom cotton picking.

Under his pivots, he plants indeterminate varieties because of their early-maturing characteristics. Getting his own cotton picked and gone before he starts picking cotton for other people is critical, he says.

For growers considering variable rate irrigation, Bowers says an accurate soil mapping system in essential. He uses a Veris rig to map his fields.

The system uses GPS and the technology of soil electrical conductivity (EC) to identify areas of contrasting soil properties. When the Veris Sensor Cart is pulled through the field, it acquires measurements, geo-referencing them using GPS.

The data collected by the Sensor Cart are then displayed on an instrument panel, along with its coordinates. The result is a map that identifies the contrasting soil conductivity.

Though Bowers’ primary benefit from variable rate irrigation is to adjust moisture content on varying soil types, there are a number of other reasons for going to variable application of irrigation water:

• Multiple crops in one field under irrigation

• Avoiding off-site areas such as roadways, highways, and wetlands areas

• Avoiding non-crop areas under a pivot

• Pond or waterway transversal

• Topography variability

• Over-lapping pivots

• Irregularly-shaped field.

Labor is a constant problem. Bowers has one full-time farm worker; his daughter helps some with his recordkeeping and his son, now in college, helps part-time on the farm.

Variable rate irrigation and computer technology allows him to do in ten minutes from his office, what used to take him 2-3 hours driving from one farm to another — just to turn his pivots on and off.

There is no doubt that his 35-plus years of on-farm experience and long days of hard work help make Bowers’ operation a success. But, in the past few years, he says technology has helped him sleep better and longer at night.

Irrigation in general, and variable rate irrigation in particular, in the past few years has helped him make better management decisions.

“I know variable rate application has made me a better farmer. I take more soil samples and I just know more about what is going on in my fields.

“The immediate benefit is uniformity in my crops. I have seen yield increases using variable rate irrigation, and there is no question it saves in water and energy costs,” Bowers says.


TAGS: Management
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