Moisture, as always, remains the most limiting factor for peanut yield and quality for Southwest producers. But growers should not ignore other best management practices that allow them to take advantage of in-season irrigation and rainfall.
Key production factors include irrigation management, variety and market type selection, weed control, rotation, disease management and tillage, says Texas AgriLife Extension pathologist and peanut specialist Jason Woodward, Lubbock Research and Extension Center.
Woodward, speaking at the annual Oklahoma Peanut Expo, said producers should know their limitations—including the market type they grow, the soils available, the rotation options, and availability of water.
He also says peanuts offer a valuable rotation for other crops, especially cotton. “Peanut is an effective rotation crop,” he says. “It responds to residual soil fertility and improves yield potential for a subsequent cotton crop.”
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He says peanuts like low organic matter soil that facilitate pegging and harvest. “Peanuts are more difficult to get out in heavier soils.”
But water is the great equalizer. “Irrigation capability is the most critical requirement for peanuts on the High Plains. Drought in the Southeast is different from drought in the Southwest.” Woodward has experienced both, growing up in Southwest Oklahoma, spending several years working peanuts in Georgia and back on the Texas High Plains for the past ten years.
“Irrigation here encourages high yields and good quality,” he says. “Many farmers grow dryland peanuts in the Southeast, and we may see a few in West Texas in 2016, but more water equals more peanuts. Water availability is, unfortunately, becoming a more limiting factor for irrigation.”
Woodward says peanuts need relatively little water early in the season, but demand picks up significantly during reproduction, which coincides with the hottest and driest part of the year. “Producers need to monitor irrigation throughout the season and be mindful of soil moisture at pegging and at harvest to minimize losses.”
Peanuts with adequate moisture also have less incidence of aflatoxin, Woodward says
Water quality also makes a difference, especially with increasing concern with salinity. “Low quality irrigation water affects yields,” he says. “With depletion of the Ogallala Aquifer, we are seeing reduced capacity and lower water quality.”
Peanuts, he adds, are less tolerant of salt than other crops, cotton for instance. Germination and stand establishment may be compromised. “We also see negative effects from salt accumulations later in the season. Damage may include severe necrosis, which may affect harvestable pods.”
Irrigation efficiency also may include effective weed control to reduce competition for moisture and nutrients, Woodward says. The basics of a sound weed management program include: Start clean and stay clean; use yellow herbicides; overlap residual herbicides; and properly identify weed species.
Some weeds, Woodward says, are excellent hosts for root knot nematodes. Weed control in a wheat/fallow rotation is important, he says, since weeds that survive in fallow fields may host nematodes. “Russian thistle, for instance is a better host for root knot nematode than is a susceptible cotton variety. Other weeds, including Palmer amaranth, nutsedge, ivy-leaf morningglory, Johnsongrass, volunteer corn and susceptible volunteer cotton also host nematodes.”
He emphasizes the value of a peanut/cotton rotation as part of a nematode management strategy. “In cotton planted behind peanuts, we see significant reduction in nematode damage. In a wheat and peanut rotation we see little nematode reproduction in the wheat crop. Nematode populations are stabilized or reduced with rotation.”
Woodward also points out that although both cotton and peanuts are susceptible to root knot nematodes, the species that affects cotton is not the same as the one that affects peanuts. “Overall, peanut is a better rotation than sorghum for nematode management in cotton.”
He says variety and market type may dictate some irrigation and disease management strategies in peanut. Earlier maturing types, such as Spanish, may produce good yields on less water. “It takes more time and water to make a runner peanut. Variety research makes up some of the most important work we do at the Texas AgriLife Research and Extension Center,” he says.
Disease susceptibility also varies with market types. Spanish types are generally less susceptible to Sclerotinia blight and pod rot but newer runners also have more resistance. The old standby, Flavorunner 458 is no longer available, replaced by other high oleic varieties, many of which have improved resistance to Sclerotinia and pod rot.
Woodward says a new wrinkle, running Spanish type peanuts, “grow like runners and grade like Spanish.” The downside is less consistent yield, he says. Valencia peanuts fit a market niche but typically produce lower yields. “We are seeing improvements in Virginia yields with the genetic gain of new Virginia varieties equal to or better than older varieties, such as Gregory. We now have a number of Spanish, Virginia and runner types that perform well.”
A key to disease management, he adds, is knowing the field history. “Know the disease in the field. If a grower has had Sclerotinia problems in the past, rotation may reduce incidence, but it will be a problem again. Budget for a fungicide.”
REDUCED SEEDING RATE
Woodward says with high production costs and low market prices, growers may be looking for ways to reduce inputs this year. Seeding rate could be a possibility. “Six seed per foot of row is the standard,” he says. “They follow that in the Southeast to safeguard against tomato spotted wilt virus (TSWV). In the ten years I’ve been in the High Plains, I’ve seen no evidence of TSWV as an economical issue.”
Reduced seeding rates might be possible, but he recommends caution. “It is possible to reduce seeding rate considerably and not see a significant yield loss. I would be comfortable reducing seeding rate to three to five per foot of row.”
Oklahoma State Extension specialist Todd Baughman adds that with a seeding rate reduction producers need to make certain planters are calibrated accurately to maintain uniformity and proper planting depth assure stands are not compromised.
Woodward says tillage is another consideration. “A lot of growers in Georgia are using a no-till system, and that could be a benefit here. A challenge in this area is the value of the water necessary to grow a cover crop. Also, watch residue that might affect getting pods out of the ground.”
Woodward says all commodity growers face significant challenges this season with high input costs and low prices. Some producers, he adds, may look for ways to cut costs and save money. But staying with proven best management practices, including sound irrigation management, effective weed and disease control and staying on a good rotation program will increase production efficiency.