13 minute read
WET-WEATHER DISEASES
BY AMANDA HUBER
SOUTHEAST EDITOR
Managing the cotton crop in many Southeast fields is presenting a challenge in 2021. Weather conditions shaped a planting window from April to June. Even into midseason, rain has prevented timely spraying and caused waterlogged soils in some areas.
Cotton responds to oversaturation of soils in different ways. Plants may become chlorotic, reduce nutrient uptake and, therefore, shoot growth. Typically when soils dry, the crop rebounds and begins to grow again. However, extended leaf wetness can lead to foliar disease.
Wet-Leaf Foliar Diseases
University of Georgia Extension plant pathologist Bob Kemerait says, “Rain and increased humidity create favorable conditions for infection and spread of target spot. Additionally, heavy rains can leach potassium from the root zone, thus increasing the risk for Stemphylium leaf spot and Cercospora leaf spot. Ascochyta ‘wet weather’ blight can also produce spots with concentric rings.” Although each of these diseases produces leaf lesions, it is the placement on the cotton plant that helps differentiate between them. Kemerait says Cercospora leaf spot, which is associated with potassium deficiency, and Stemphylium leaf spot appear first in the upper leaves.
Scouting Is A Must
Auburn University Extension plant pathologist Amanda Strayer-Scherer says areolate mildew is another fungal disease that begins in the lower canopy and can cause premature defoliation.
“Target spot pressure is normally heaviest in southwest
Alabama, and symptoms include irregular-sized leaf spots with concentric rings. Areolate mildew is easily identified by a white mildew covering parts of or entire leaves.” Fungicides should be applied preventatively for target spot starting at the first or third week of bloom followed by a second application at the third or fifth week. To Improve Fungicide “Alternatively, you can apply fungicides at the first sign of Coverage: target spot or areolate mildew and apply a second application Increase the spray volume as needed. However, keep in mind that target spot can be difand pressure. ficult to control with fungicides if 25% to 30% of the leaves are If possible, make the first already gone. Priaxor, Revytek, Elatus and Miravis Top should application before canopy do well against both diseases,” she says. closure.
Improve Application Coverage
Kemerait says it can be a challenge protecting the crop against a disease such as target spot where fungicide coverage is needed deep in the canopy. “Getting sufficient fungicide coverage can be improved by increasing spray volume, increasing spray pressure and making the first fungicide application early enough before the canopy of leaves is fully closed.” This is one reason farmers are advised to scout the crop often checking the lower canopy for tell-tale symptomatic leaves. “If target spot is not identified after scouting, growers may delay a fungicide application and scout again in the coming weeks. Fungicides are not needed after the sixth week of bloom.”
Target spot symptoms include irregular- sized leaf spots with concentric rings.
DR. BOB KEMERAIT UNIVERSITY OF GEORGIA
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Sustainability Story Shared
Cotton Council International, the National Cotton Council’s export promotion arm, is educating manufacturers, mills and brands/retailers on why U.S. cotton is the “The Cotton The World Trusts” to drive the fiber’s export growth.
How important is sustainability to creating demand?
■ Although U.S. cotton producers traditionally have led the world in innovation, quality and responsible stewardship, there is not enough awareness of their efforts to produce more sustainably grown cotton. That’s why sustainability now is a core component of CCI’s export promotion strategy. CCI shares U.S. cotton producers’ leadership in and commitment to sustainable growing practices with mills, manufacturers, and brands/retailers around the globe.
Levi Strauss, Gap and Gildan are among the more than 450 members that have joined the Trust Protocol since the program’s 2020 launch.
Brands and retailers are under more pressure to embrace sustainability, including proving they are doing their part to combat climate change, but they have lacked the data to do so. No doubt, the demand for more sustainably produced products will mean U.S. cotton producers must show their past and future commitments.
Fortunately, the U.S. Cotton Trust Protocol® is proving to be a great vehicle for providing brands and retailers with a measurable sustainability program and the confidence they need to source U.S. cotton. That’s because the program aggregates yearover-year data on critical metrics including water use, greenhouse gas emissions, energy use, soil carbon, soil loss and land use efficiency. U.S. cotton producers’ participation in this data-backed and third-party verified program also provides another significant benefit — it draws important attention to their commitment to “continuous improvement.”
What about Trust Protocol participation?
■ To demonstrate their sustainable stewardship, about 300 U.S. cotton producers were fully enrolled in the Trust Protocol for the 2020 crop. For those producers who want to enroll their 2021 crop, click the Join Now button at the top of the Trust Protocol website’s home page, www.trustuscotton.org.
The Trust Protocol has welcomed more than 450 members since its launch in 2020. This includes Levi Strauss & Co, one of the most recognizable denim companies worldwide, and its legacy brands Levi’s®, Dockers®, Denizen® by Levi’s®, and Signature by Levi Strauss & Co.™; Gap Inc. and its collection of purpose-led lifestyle brands Old Navy, Gap, Banana Republic and Athleta as well as global apparel manufacturer Gildan.
Some Trust Protocol brand/retailer members, in fact, are participating in the pilot phase of the Protocol Credit Management System, which provides its members with complete supply chain transparency through use of TextileGenesis’ blockchain technology.
U.S. cotton textile mills — including Buhler Quality Yarns, Cap Yarns, CCW, Contempora Fabrics, Cotswold Industries Inc., Frontier Yarns, Hamrick Mills, Inman Mills, Parkdale Inc. and Swisstex Direct — were some of the first to join the Trust Protocol. They were featured in a public relations campaign highlighting their transparency and sustainability to raise awareness of the individual companies and their products.
Parking The Sandfighter
West Texas Growers Adopt No-Till Coupled With Cover Crops To Reduce Erosion And Protect Young Cotton Plants
BY VICKY BOYD
MANAGING EDITOR
West Texas cotton producers Kris Verett and Ian McIntosh have adopted conservation tillage coupled with cover crops over the past few years for different reasons, but soil health has not led that list.
“We needed to look at something different in 2010 when it was so dry and we and everybody was struggling with the crop,” says Verett, who farms with his father and uncle near Ralls, Texas. They transitioned to no-till that year and in 2013 began adopting cover crops.
McIntosh, who farms with his father near Floydada, says they began using no-till into wheat stubble in the early 2000s to address labor needs.
“It became real obvious,” McIntosh says. “We didn’t have a lot of help. It was just me and Dad and a hired hand. We were just trying to minimize the trips in the field.
What the two producers do share is their disdain for the sandfighter — or rotary hoe — after a rainstorm, and minimum tillage combined with cover crops help avoid the equipment.
Challenges To Adoption
Calvin Trostle, an Extension specialist and professor in the Department of Soil and Crop Sciences at Texas A&M AgriLife Research in Lubbock, has worked with conservation tillage and cover crops for more than two decades. And he says Verett’s and McIntosh’s motivations are in line with those of other West Texas growers with whom he’s met.
Kris Verett is experimenting with 80-inch row spacings this year on a half circle of cotton. His seed costs were cut by about 40%. Although he plans to broadcast herbicide, he will band nutrients and crop protection materials. At the end of the season, Verett will compare the 80-inch performance and costs to an adjacent field on 40-inch rows.
KRIS VERETT | Ralls, Texas
Kris Verett, who farms with his father and uncle near Ralls, Texas, credits a field day hosted by R.N. Hopper of Petersburg, Texas, for planting the cover crop seed.
“I immediately thought, this is what we need to be looking at,” he says.
The family had moved to no-till in 2010 and began implementing cover crops in 2013. Their system begins immediately after cotton harvest with planting a winter cover of cereal rye, haygrazer (sorghum-sudangrass hybrids), millet or other grass species. Verett uses a Case I-H planter equipped with Yetter finger-style row cleaners and depth band along with spiked vertical closing disks.
During most years, cover crops help capture heavy rainfall, slowing runoff and allowing it to percolate into the soil, he says Without the vegetation, rainfall frequently runs off their fields, taking soil with it. In the long run, Verett says, cover crops yield a net benefit as far as soil moisture.
Normally, Verett terminates the cover crop in late winter or early spring before it goes to seed to reduce volunteers. But with rye seed prices double what they have been, Verett let some fields go to seed for harvest this spring.
Come August or September, he returns to plant a warm-season cover blend that may include up to 10 species of grasses, such as spelt or triticale, radishes and legumes.
On his irrigated ground, Verett may apply 0.25 inch to spur cover crop germination. With his dryland ground, he relies entirely on rainfall.
He also has begun partnering with a cattle operator who shares a similar land stewarding philosophy to implement mob grazing on some fields. During the intensive rotational grazing, cattle eat a portion of the cover while still leaving a significant amount of plant biomass. Their manure also helps return nutrients to the soil.
As a result, the practice provides a revenue stream during the period when fields are in cover crops.
As with anything living, though, Verett says their cover crop program is still evolving.
“We’re constantly learning,” he says. “As a system, this thing is changing. I don’t ever see getting to a static position on this stuff.”
That said, Verett can’t envision returning to a program without covers because of the positive impact they have made on their bottom line.
“We’re reducing hours on equipment and fuel use by 70%. It’s just phenomenal,” he says.
Before, they would make two to three passes just for tillage, not counting the additional passes with the sandfighter.
Now they pull the drill to plant a cover crop using a much lighter tractor and possibly make one pass with a spray rig. And rarely does the sandfighter enter a field.
IAN MCINTOSH Floydada, Texas
Ian McIntosh, who farms with his father near Floydada, has about two-thirds dryland and one-third irrigated ground. Since the early 2000s, they have no-till planted their cotton into harvested wheat stubble.
“We’re so dry around here that dryland farming with growing a cover crop is usually a miss because you can’t count on the rain,” he says. “Under the pivots, it’s cotton behind cotton, and winter wheat is the only thing that will grow and give us cover.”
McIntosh has been working with consultant Jeff Miller to look at different mixes suited to the dry West Texas plains. One that McIntosh liked was a summer grazer blend that grew 6 feet tall and included flowering cowpea, sun hemp, sudangrass, millet, okra and radish.
Based on the planting rate and species mix, cover crops can be pricey. But Environmental Quality Incentive Program funds may be available to help offset part of the cost, depending on county priorities.
McIntosh says he tries to shoot for $13 to $15 per acre. In one of his worst fields, he realized he had spent about double that after he finished planting.
His targeted budget is in line with recommendations from Calvin Trostle, an Extension specialist and professor in the Department of Soil and Crop Sciences at Texas A&M AgriLife Research in Lubbock. Trostle says he believes cover crop seed costs should not exceed $1 per acre for each inch of average rainfall — plus irrigation, if used. This limits their cost in drier parts of West Texas to no more than $16 to $18 per acre.
When the efficacy of glyphosate began to fade, McIntosh began looking to intentionally grow cover crops to compete against weeds.
“With the summer grazer, I planted it in late July, and it was the last I sprayed preplant because it had so much cover,” he says. “The weeds just didn’t have the sunlight until it got warmer.”
McIntosh uses his normal planter with trash wheels on the front to help move plant residue away and allow for better seed-to-soil contact. He also has changed out his V closure chain for two disks and a press wheel.
As part of his weed-control program, McIntosh relies on Enlist herbicides and PhytoGen varieties with the Enlist trait.
On McIntosh’s dryland ground, PhytoGen PHY 300 W3FE is a mainstay. Under his pivots, the West Texas stripper variety, PhytoGen PHY 394 W3FE, has worked well.
“When I stick that seed in the ground, I want to know it’s sprouting and coming up,” he says.
Floydada, Texas, cotton producer Ian McIntosh has been a proponent of no-till planting into terminated wheat for nearly two decades.
Even if growers don’t want to dive into cover crops, Trostle says, they can obtain partial benefits by reducing tillage and keeping more plant residue on the soil surface.
“When you do tillage operations, you may be setting your land up for more erosion from wind,” Trostle says.
Probably the most common cover in West Texas is terminated wheat or rye into which the subsequent cotton crop is drilled, he says.
Katie Lewis, an associate professor of soil chemistry and fertility with joint appointments at Texas Tech and Texas A&M AgriLife Research, says cover crop adoption in Texas lags that of many other states.
The U.S. Department of Agriculture’s National Agricultural Statistics Service estimated that cover crops were planted on only 8% of Texas cropped acres in 2018. Conservation tillage — whether no-till, strip till or targeted tillage — was practiced on 37% of cropped acres.
Particularly in West Texas, the 17-19 inches of average annual precipitation can be a deterrent to using covers, she says.
Trostle agrees and says cover crop’s water requirements are a major concern when he’s conducted grower meetings. Cover crops typically need 2 to 4 inches of moisture over the winter to ensure they produce enough plant growth and biomass to provide soil protection. But that’s just part of the equation.
Citing research conducted in Akron, Colorado, Trostle says cover crops didn’t negatively affect water use within a cropping system.
Although many growers say soil health is not a driver behind their cultural conservation practices, Lewis says they frequently talk about factors — such as seeing more earthworms in the soil — that indicate soil health improvements.
For more information on cover crops, download Trostle’s guide — “Fall Cover Cropping for Texas—Is it for you? How many species should I plant and what should I pay?” — from Texas A&M AgriLife Extension Service at https://bit.ly/3r1jnuy
