A Look Back - 30 Years
Coloradan Plans Minimum Till, Chemical Fallow / By Don Lilleboe — “Normal annual precipitation around the southeastern Colorado community of Eads is 15 inches. Usually, the snow that does fall during winter rarely stays around for long. So when the wind blows, as it does frequently, a lot of soil goes with it.
“Eads farmer John Larson contends that in a production environment such as this, minimum- or no-till cropping systems should no longer be considered an option, but a necessity. ‘The major problem we have here,’ he says, is holding the ground after harvest.’
“Larson experimented with various sunflower cropping practices during 1982 in an effort to learn which system will do the best job of helping him attain projected yields of about 1,000 pounds per acre while simultaneously keeping soil erosion to a minimum and conserving soil moisture.
“Part of Larson’s ’82 sunflower acreage went into conventional tillage, i.e., planted in 48-inch rows with a lister and then cultivated during the season. The remainder of his sunflower was planted with an air seeder in 28-inch rows — but in five different manners:
• into hailed-out wheat ground, with chisel points on;
• into wheat stubble, with points;
• into wheat stubble, with sweeps on;
• into ground which had been chemically fallowed since the previous wheat harvest, with points on;
• into chemically fallowed ground with sweeps on the seeder. . .
“Larson averaged about 850 pounds of sunflower seed on his total harvested acreage, even though the hailed wheat ground went only 300. The yield on the chemically fallowed ground was closer to 1,100-1,200 pounds per acre.
“He plans to put all his 1983 sunflower acreage on ground which was chemically fallowed following the ’82 wheat harvest; and he believes that with increased crop residue and an abnormal amount of snow received this winter, prospects for ’83 yields are very good.”
Get the Jump on Cutworms — “Cutworms can be very destructive to a field of sunflower seedlings. Feeding at, just above or just below ground level, they chew on the plant stalk until it is cut off — then move on to the next plant. If a grower plans ahead and is prepared to stop cutworm damage when it begins, losses can often be minimized.
“ ‘Early detection and early treatment are two vital factors in stopping cutworm damage in sunflower fields,’ reports Dean McBride, extension entomologist with North Dakota State University. ‘Cutworm larvae typically feed at night, and, particularly with crusted soil conditions, they’ll stay just under the soil surface during the daytime. Thus, the only way to really determine if there is a cutworm infestation is to get out into the field, dig around and scout for them. We advise that a farmer begin scouting at plant emergence and continue at least twice a week until about mid-June. . . .
“ ‘The economic threshold for cutworms in sunflower is one larva per square foot or 25-30 percent stand reduction in the immediate infestation area,’ McBride explains.”
A Look at the Export Scene for Seed & Oil / By Don Lilleboe — “Thank heaven for the Mexicans, Portuguese and U.S. government commodity credit programs.
“That might be the proper advice for the U.S. sunflower industry in this spring of 1983. Because of the Mexicans buying our seed and oil — and credit programs facilitating their doing so — domestic sunflower seed prices were able to stage a moderate rally (about $20 a metric ton) during March; thus shedding some light on a market which had experienced some real winter ‘blahs.’
“U.S. sunflower’s dependence on foreign markets is hardly a secret. As either seed or oil, the great majority of our domestic production ends up in export pipelines. Yet burdensome world oilseed supplies, increased rapeseed and sunflower production in France, the high price of U.S. sun oil compared to its subsidized Argentine competitor, and a struggling world economy, have all combined to exert downward pressure on U.S. sunflower seed price levels. And it appears these factors will continue to restrict prices for the remainder of the current marketing year.”
Plant Chemicals Help Repel Insects — “When scientists at the USDA Conservation and Production Research Laboratory at Bushland, Texas, observed that some wild species of sunflower were more resistant to attacks by certain insect pests than were cultivated varieties, they wanted to know why. And when they could find no obvious structural feature on the wild plants to account for this natural resistance, they wondered if there could be a chemical basis. . . .
“To help find out, they turned to Dr. Tom Mabry, chairman of the University of Texas botany department, and Jonathan Gershenzon, a UT graduate student. With support from the National Sunflower Association and the National Institute of Health, Mabry and Gershenzon have now completed a detailed chemical analysis of hundreds of populations of wild sunflower collected during a 10,000- mile trip throughout the United States.
“Mabry and Gershenzon discovered that the insect-resistant plants were extremely rich in two types of chemical compounds of the terpene class which are toxic to insects. . . .
“After isolating large quantities of the chemicals (which were concentrated on microscopic hairs on the leaf surface and flower parts), the botanists added the chemicals to the diets of sunflower moth larvae. . . . [They] found that most of the insects were repelled by the altered diet — and ended up starving.”
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