Drought, Stand Top ’02 Sunflower Yield Robbers
Saturday, November 2, 2002
filed under: Optimizing Plant Development/Yields
Drought and poor stand establishment are two of the most significant sunflower production problems evident this year, according to a pre-harvest survey of sunflower fields across the U.S. sunflower production area, conducted in September.
Coordinated by the National Sunflower Association, this year’s sunflower survey is the most intensive ever, with 450 sunflower fields surveyed across the plains. One field was surveyed for every 5,000 acres of sunflower in sunflower-producing states. There were 238 fields surveyed in North Dakota; 131 in South Dakota; 31 in Kansas; 19 in Colorado; 12 in Nebraska; 12 in Texas; six in Minnesota; and one in Missouri.
Close to 300 people were involved with conducting the survey. Before heading out to the fields, survey participants attended a mini seminar on sunflower production, learning how to estimate sunflower yields, identify weeds and other sunflower pests, and determine damage. Agronomists who participated earned continuing education credits, required for certified crop advisers. “It’s a good training tool to increase expertise in sunflower production,” says Roger Stockton, Kansas State University extension crops and soils specialist. “There were five county extension agents in Kansas that went through the training and sampling, and feel a lot more confident about dealing with sunflower now.”
A number of factors were surveyed and sampled in each field: Plant population, row spacing, tillage practice, pest problems (both the edges and interior of a field), lodging, webbing, top yield limiting factors, and yield potential. The NSA’s pre-harvest yield survey was within 100 pounds of the USDA’s preliminary yield estimate in all states, except North Dakota. The NSA survey yield estimate for N.D. (which did not take abandoned or harvested acreage into account) was 1,622 lbs/ac; the USDA’s estimate for N.D. released on October 1 was forecast at 1,250 pounds per acre.
Global Information Systems (GIS) technology was used during the survey process, allowing field data to be geographically mapped to see where production problems lie. This data, mapped by John Nowatzki at North Dakota State University, will be posted on the Internet by December 1. A link to this information will be available on the NSA’s web site, www.sunflowernsa.com.
Max Dietrich, the NSA’s production coordinator and survey organizer, says that the U.S. sunflower survey data is important in a number of ways. It allows the industry to get a head’s up on the new crop’s quality and size, as well as production challenges. Results from the survey are used to develop sunflower research priorities for 2003. The survey also provides information that can justify an application for emergency exemptions for needed pesticides, and is a valuable tool for companies in assessing new products for the sunflower industry. Dietrich points out that the survey data also helps producers assess their production problems, and make management adjustments next year. “We appreciate the cooperation of sunflower producers across the U.S. whose fields were included in the survey,” he says.
Following are highlights of the survey, with results summarized by Art Lamey, professor emeritus at NDSU.
Yield and Plant Population
Average yield (oil and confection combined) in drought-stressed Colorado was estimated at 672 lbs/ac, and plant population, 6,167 plants/ac. KS: 919; 10,900. MN: 1,894; 16,908. SD: 1,124; 11,636. ND: 1,622; 15,598. TX: 1,019; 11,732. There was a fairly close correlation between plant population and yield; the better the stand, the better the yield potential. Drought obviously impacted emergence, but poor seed to soil contact and early insect damage such as cutworms and wire worms may have contributed. The NSA research committee has identified stand establishment as a high research priority for the 2003 season.
Row Spacing
Sunflower in most states was planted at a row spacing greater than 20 inches, with the exception of Texas, which was virtually all narrow rows. That’s due largely to sunflower planted with the same equipment as cotton, which is planted in narrow rows. Narrow rows were also more common in the central and western parts of the Dakotas, where no-till planting and solid seeding is more commonplace.
Tillage
No-till sunflower was most predominant in Kansas and South Dakota. Surveyors classified mechanical soil disturbance, including one-pass planting systems that incorporate sweeps, as minimum till, which was most predominant in Colorado and Nebraska.
Weeds
Certain weeds, not surprisingly, were more predominant in some states than others, although kochia seemed to be problematic across the board. The higher weed presence in some areas, such as Texas, is a concern; not only do weeds steal precious moisture away from sunflower plants, they present a quality problem, most significant in confection sunflower, which was planted on about two thirds of Texas sunflower acreage this year. Volunteer grains were a problem in the High Plains, perhaps a function of soil conditions too dry for pre-plant and pre-emergent herbicide application.
Ground Lodging
The high percentage of ground lodging in Kansas can be almost entirely attributed to stem weevil infestation, which was high this year in Kansas.
Diseases
Disease incidence was low overall, but there were hot spots; most noticeable, the18% incidence of verticillium in South Dakota, which was as high as 59% in the south central part of the state. Incidence of rhizopus was about 10% in Kansas, Texas, and northwest South Dakota. Head rot incidence approached 10% in Minnesota and the central part of North Dakota. While disease incidence does not reflect disease severity, and may not result in yield loss, areas where disease was a problem need to be monitored. Verticillium, for example, is a soil-borne fungus and can carry over to the next growing season, notes USDA-ARS plant pathologist Tom Gulya.
Bird damage
Statistically, bird damage was most noticeable in Minnesota, where about 6% of sunflower fields surveyed overall had some bird damage. However, perimeter damage was over 10% in south central, northwest, and west central South Dakota, and northeast North Dakota. Bird damage occurring after fields were surveyed in September would not be reflected in these figures.
Insects
The spotted stem weevil appears to be the most prevalent insect problem this season, found in about 70% of fields surveyed in Kansas and Nebraska and nearly 60% of South Dakota fields. Some midge activity could be found in fields in the Dakotas and Minnesota, but was generally minor. The soybean stem borer (also called the long-horned beetle, or Dectes stem borer) could be found in almost 40% of sunflower fields in Kansas, and over 20% of fields in Texas and South Dakota. The insect, which migrates to and can feed on soybeans, sunflower, and other broadleaves, needs to be monitored. More details on insect damage will be available as USDA-ARS entomologists finish analyzing seed samples taken during the survey. – Tracy Sayler
Top Reasons for U.S. Sunflower Yield Losses in 2002
Based on September National Sunflower Association Crop Survey
Colorado Drought Poor stand/plant population
Kansas Drought Insects
Minnesota Poor stand/plant population Weeds
Missouri Poor stand/plant population
Nebraska Poor stand/plant population Drought
North Central SD Poor stand/plant population Drought
Central SD Drought Poor stand/plant population
South Central SD Drought Poor stand/plant population
North West SD Drought Insects
West Central SD Drought Insects
South West SD Drought Poor stand/plant population
North East ND Disease Birds
East Central ND Disease Birds
South East ND Poor stand/plant population Drought
North Central ND Weeds Poor stand/plant population
Central ND Poor stand/plant population Disease
South Central ND Drought Weeds
North West ND Disease Hail
West Central ND Drought Poor stand/plant population
South West ND Drought Weeds