Zero grade irrigation is more understood and widely accepted the further west in the nation you go, but some Louisiana producers are on the cutting edge for the Mid-South and are adopting the modern irrigation method with solid success.
Zero grade irrigation, also called level basin irrigation, involves precision leveling of a field to a 0 percent decline (level) with the use of laser leveling technology and using flood irrigation to water fields in timed sets depending on soil type and pumping capacity. About 10,000 acres of row crops in Louisiana are at zero grade and about 2,500 acres are converted to the system each year. About 1 million acres of land in the nation's Southwest are irrigated with the system.
One of the most significant positive factors is glaring for producers this season — that is the savings reaped in fuels costs from not having to turn the pumps on as often as needed with furrow or pivot irrigation.
Lee Bean, one of the managers of Angelina Plantation, a 26,000-acre rice, soybean, grain sorghum, wheat and oat farm near Monterey, La., in Concordia Parish, has been gradually leveling fields for zero grade irrigation and plans to continue to put more of the farm's fields into the system.
“I started back in the '70s wanting to try this zero grade system, but I couldn't get anyone interested in it,” says Bean. Now several thousand acres of Angelina Plantation are flooded under the zero-grade system, which allows them to get water on and off fast, using less water and less labor.
“We precision leveled rice and soybean land and built levees, roads, and ditches. We installed an irrigation system for each 80-acre field for a cost of $402 per acre,” says Bean.
“We pump water on the field to establish a flood and turn the pump off,” Bean says. “It's like putting water in a pond. The fields stay flooded until the water is drained from the field.”
The fields have ditches on three sides, which help to quickly cover the field with water or drain excess water from the field following a rain.
“There is little need for a shovel in a zero grade field, and water level can be checked at any location in the field,” Bean says. “This saves a lot of time and labor.”
Bean says his experience shows the total amount of water needed to produce rice in a season can be reduced using zero grade techniques rather than conventional rice irrigation methods.
“Successful farming is a game of pennies,” Bean says. “And farmers must be efficient in all segments of their business.”
Bert Clemmens, director of the USDA's Water Conservation Laboratory in Phoenix, Ariz., speaking at a recent irrigation and water conservation meeting in Vidalia, says level basin irrigation in verification fields resulted in yield increases of 20 to 40 percent; water and labor savings of 35 to 40 percent; and 10 percent less land taken out of production. “Level basins have low labor requirements because there is no need to guide or control water to individual furrows,” says Clemmens.
Clemmens adds, however, that the system isn't for everyone.
“There are some limitations. You need relatively uniform soils. For large basins you need to have a large flow rate. Also, light applications of water are not always possible. On heavy soils and/or with high rainfall, excessive inundations can result,” says Clemmens.
“However, level basins are a well-proven modern irrigation method.”
Bean says he sees on Angelina Farm the same positive trends documented in Arizona.
“Zero grade is easier; we use less labor; we save water; and we increase yields.”
The system at Angelina allows him to reclaim irrigation water through a tailwater recovery system. Water from 800 acres all goes into one canal and can be pumped back out and used to flood the fields again.
“We are blessed now in that we have the water we need, but that is not always going to be the case,” says Bean. “In the future, water will be worth more than the ground.”
Bean says critics of the system tell him there will be a year when it rains so much that the zero-grade won't allow him to get the water off fast enough, but he says that hasn't happened. In fact it was fields on a 2 percent slope that he had to replant because the water stood on the field too long after planting.
Bean, and Tommy Ellett, also a farm manager at Angelina, work closely with the Extension Service, USDA and the Natural Resources and Conservation Service, to fine-tune their zero grade approach and allow the agencies to document their methods and results.
Bean says that with the expertise at their disposal and the positive results they've gotten since 1996 with the zero grade system, they are ready to try the system on cotton. “This is good technology,” says Bean. “It gives us more control on any crop we have.”
Dan Thomas, head of the department of biological and ag engineering at Louisiana State University, says plans are to do some modeling of the system and verification to see how the water moves across the fields and to provide growers with more precise information on the size of spin ditches and length of flood, etc.