Irrigated Sunflower Good Fit in Neb. Strip-Tilll
Wednesday, December 1, 2010
filed under: Irrigation/Water Use
Jim Darnell uses a four-letter word when explaining why he produces all of his row crops under a strip-till system: wind. “Our biggest issue around here is wind erosion in the spring,” says the western Nebraska producer. “Everyone tries to do something to stop erosion.”
Darnell has raised sugarbeets under strip till for 13 years on his farm north of Scottsbluff. It’s been a more-recent development with his other row crops — corn, dry beans and sunflower. The 2010 season was the fifth in which Darnell has grown confection sunflower under a strip-till regimen.
Prior to strip till catching on, growers in Darnell’s area commonly used a straight plow-plant approach, i.e., moldboard plow a couple days ahead of planting, pulling a packer behind the plow to break down clods and firm the seedbed. While it usually resulted in an acceptable seedbed, that system was not very effective at blunting those strong spring winds sweeping across the Nebraska Panhandle. Darnell tried minimum tillage; then even ridge till — which worked fine with corn and beans, but not so well in beets. Strip till finally filled the bill.
Darnell’s strip-till machine is a 12-row Case-DMI NTX5310 with 24” coulters and high-clearance shanks, which he pulls at an 8-9” depth. Sunflower follows corn in his rotation. After running a rolling stalk chopper through the standing corn, he’ll come back with the strip-till unit, running it right atop the old corn rows. RTK auto steer helps keep the machine on top of the rows.
Twelve gallons of 10-34-0 and eight gallons of 32% N are applied during the strip-till pass. About half is placed at the bottom of the shank and the other half a couple inches beneath the seed zone. (The remainder of the sunflower fertility needs are either sidedressed or applied through the center pivot.)
For sunflower, Darnell typically pulls in with his Case IH Early Riser 1200 Series planter one to three days after the strip-till pass is performed. His per-acre confection seed planting rate normally runs around 19,000. If he’s planting a Clearfield® variety, Beyond naturally comprises his herbicide program; if planting another variety, it will be a mixture of Spartan and Prowl.
About three-fourths of Darnell’s sunflower acreage is produced under center-pivot irrigation, with the remainder being gravity (furrow) irrigated. He says the gravity-irrigated fields generally out-yield the center pivot ones. The main reason, he believes, is his ability to apply more water per treatment with the gravity system. While many center-pivot producers may irrigate their ’flowers only two or three times per season, Darnell finds he must make several applications to meet or exceed his 2,500-lb yield goal.
Though he hasn’t conducted any side-by-side comparisons of yield and seed size of confections that are under strip till versus other tillage systems, Darnell is confident he’s harvesting sunflower crops that are at least as productive — if not more so — than conventional, no-till or other reduced-tillage systems.
Strip-tilled sunflower ground goes back into corn the following year. However, “we don’t strip till behind the sunflower,” Darnell relates. “The ground is so mellow and loose in the row that we just go over it with a rolling stalk chopper and plant the corn. Those [sunflower] roots have gone down and broken up any compaction.” Not tilling the old sunflower rows also leaves more surface residue to help protect the young corn plants, he points out.
Along with halting erosion from spring winds, Jim Darnell highlights two more benefits to his strip-till program: savings in time and savings in fuel from the fewer passes across the field. He especially appreciates the time savings: “You can buy more fuel if you have to, but you have only so much time.” — Don Lilleboe