Delta growers who think no-till cotton is a practice best-suited for the hill areas of Tennessee and Mississippi should consider a visit to the Coolidge, Ariz., farm of Howard Wuertz.
Wuertz, who may be best-known for his work with subsurface drip irrigation, farms 3,500 acres in the Arizona desert southeast of Phoenix with sons Greg and David. Most of the land, which has a slight grade to help with furrow irrigation, has little potential for erosion.
“We did not do any preplant tillage in this field, and we didn't cultivate it a single time after planting,” Wuertz told a group of editors. “We hardly had any weeds in the field because there was a batten of wheat straw about 3 inches thick between the rows.”
Technically speaking, Wuertz's planting system is not strict no-till — he uses a rig he and his sons developed to peel a small portion of stubble and soil from the top of the bed. But it's close enough for most no-till farmers.
The peel-off rig, for which Wuertz and his sons have applied for a patent, is one of several tools family members have developed for use with subsurface drip irrigation.
“You know a lot of people when they peel off their clothes look better than they do with their clothes on,” said Wuertz. “The bed we plant cotton on looks a lot better when we peel it off.”
Crop residue from winter covers or natural vegetation usually goes hand-in-hand with no-till, but, in Wuertz's case, it's all part of a complex system aimed at making higher yields with less expense.
“This field produced 3 tons (100 bushels) of durum wheat per acre when we harvested it in late May,” said Wuertz. “We planted it in Deltapine 451 BR/RR in the first three or four days of June. We sprayed it with Roundup in the little area that we bared off, and that was all.”
Wuertz believes other varieties of wheat could produce up to 8,000 pounds (133 bushels) of wheat per acre. “We've done it a few times, but not consistently. When we've planted Baretta barley, we've gone as high as 10,000 pounds. And then we planted a crop of cotton that produced 3.5 bales per acre.”
Eliminating preplant tillage and cultivation and one-pass planting — they mount the peel-off rig on the front of the tractor and the planter on the back — also saves energy. “We reduced our fuel expenditures this year by about 20 percent with a 30 percent increase in fuel costs,” said Greg Wuertz.
Although it fits in with their no-till system, the peel-off rig was designed to enhance the farm's subsurface drip irrigation. Unlike many who have attempted drip irrigation with tubes lying above ground, the Wuertzes bury their tubes about 8 inches below the surface.
Howard installed the first subsurface drip irrigation system on the family's Sundance Farms 24 years ago. Since then, he's added systems to other fields so that the farm is now about 50 percent subsurface-drip irrigated and 50 percent furrow or flood.
“We like to make sure that when we pre-irrigate, which only takes 2 or 3 inches of water through the drip tubes, we get the water clear to the top of the row so that the whole bed is wet,” said Howard. “If you can't drive the water up to where you're going to put the seed, don't seed it.
“We use the peel-off rig to remove a portion of the bed to get down closer to the drip tube,” he said. “You get a perfect stand because you plant in moisture that's at the proper level.”
The idea is to try to keep the field in a working range between the point where the soil is too wet or too dry. “We don't want to have watered it the day before and try to plant, said Howard. “We want to water it, let the moisture settle out and be clearly in the working range, peel off the extra and plant.
“There are two reasons for that: One is that the salts always go to the periphery of the wetted front. So we want to peel off the part where a little salt has accumulated in the water. And, two, we want to get closer to the tube where there's good moisture.”
Not using deep tillage, the Wuertzes reduce the risk of plowing up irrigation tubes. Not cultivating or flood-irrigating also provides benefits that aren't obvious.
“Plants want their roots as close to the surface as they can because they need air,” said Howard. “With aeration, microorganisms can convert nitrogen to NO3 or P to P2O5 or K to K2O in the first 4 inches. Where you flood irrigate or cultivate, the roots get dry or the capillaries are broken.”
Howard asked his visitors to notice the soil surface in the no-till cotton behind wheat.
“When you sub-irrigate with drip the ground is softer than when you flood irrigate,” he said. “When you furrow or flood irrigate, you re-consolidate the soil particles and drive the oxygen out of the soil. That's why the old-timers said you have to get air back into the soil.”
With subsurface irrigation, he said, the water moves up from below and the soil tends to expand as it takes in moisture and air through the pores. “Where you're standing, the ground is as soft as it possibly can be. It has been watered from down up, and that tends to stand and make it well-aerated because you fluffed it up, if you will.”
Howard also told his visitors the no-till field did not receive any nitrogen after the wheat was harvested. “The residual came out of the wheat,” he said. “This did not get any additional applications after we planted the cotton.”
No Pix or mepiquat chloride was applied to the field.
Subsurface drip usually requires 2 to 3 acre feet of water compared to 6 feet of water for furrow or flood irrigation. With water costs at $34 an acre foot when Howard was interviewed, the Wuertzes save at least $100 per acre on water costs with subsurface drip.
“We've also found we can produce up to a bale an acre more cotton with subsurface drip,” said Howard, “especially if we plant right behind a grain crop.”
The new stacked gene cotton varieties, such as the DP 451 BG/RR, DP 449 BG/RR and DP 555 BG/RR, Howard has planted on Sundance Farms also are a good fit with the no-till planting.
“The Roundup Ready and the Bt cotton make it a whole lot easier for us because we don't have to worry about the pink bollworm, and we don't have to till the field at all,” he said. “I think these new varieties are the best of the best that we've ever used.”
Asked if he thought his no-till/subsurface drip irrigation would work in the Southeast, Howard said he definitely does, judging from his experience on an irrigation task force that traveled through several Southern states.
“We were in Arkansas, and they explained how they were taking water from a bayou and moving it through canals to a field,” he noted. “We asked them why they did that?
“The answer was that ‘we're always only two weeks from a disaster,’” he said. “If it doesn't rain while the crop is heavily fruiting, flowering and fruiting, it can cut the yield by 50 percent. We want to be able to give it a little drink in that period when Mother Nature doesn't bring it to us.”
Howard said the conversation convinced him of the potential to double a farmer's yield when Mother Nature holds back two weeks or 18 days. “That's why you need to put in subsurface drip irrigation. In most cases, you could put it in every other row and do all kind of things and put a little water in the profile to make the crop.”