SUNFLOWER CROP SURVEY IN THE PRAIRIE STATES: YIELD AND MANAGEMENT PRACTICES ARTHUR LAMEY AND MAX DIETRICH Professor Emeritus, North Dakota State University, Fargo, ND 58105; National Sunflower Association, Bismarck, ND; A field survey in eight sunflower-producing states was conducted in August and September 2002. It was similar to a 2001 survey in North Dakota and South Dakota (1). Both surveys estimated yield and plant population and determined class (oil or confection), use of certain cultural practices, weed intensity, insect damage, bird damage, lodging, and disease infection. In addition, seeds from each field surveyed were sampled for subsequent laboratory determination of insect damage to the seed. Materials and Methods. One field was surveyed for every 5,000 acres in each state and county, based on the planted areas in 2001. Survey teams of three or four persons were organized for each state and training was provided at the beginning of the survey. During the training each team member received a 3-ring notebook containing illustrations of weeds, insects and diseases, several assessment keys, instructions on estimating yield and plant population, three data recording forms and a master summary sheet. Each team had a specific area to survey, and a specific number of fields to survey. The location of each field surveyed was to be determined using a hand-held GPS unit. However, since not all teams had GPS units, some teams recorded the mileage and direction from nearby towns. Two teams surveyed 19 fields in Colorado, 6 teams surveyed 31 fields in Kansas, 1 team surveyed 6 fields in Minnesota, 1 team surveyed 1 field in Missouri, 1 team surveyed 12 fields in Nebraska, 21 teams surveyed 265 fields in North Dakota, 13 teams surveyed 131 fields in South Dakota and 1 team surveyed 12 fields in Texas. Survey dates in the high plains were Sept. 9-13. South Dakota survey dates were Sept. 16-17. Survey dates in Eastern North Dakota and Minnesota were Sept. 18-19 and in western North Dakota they were Sept. 25-26. Yield was estimated by determining plant population, head diameter, seed size, percent good seed and center seed set for two 25 foot measured rows (or two 5 X 25 foot measured areas in solid-seeded fields). The areas used for yield estimations were selected as typical of the field. The class of sunflower was recorded, row spacing was recorded as greater or lesser than 20 inches and the tillage was listed as no till, minimum till or conventional till. No till was defined to have no soil disturbance, and minimum till to have only slight soil disturbance. Data on plant population and estimated yield calculations were entered on a data recording form that also listed 29 common weeds and their prevalence, and the major yield limiting factor for each field. The 29 common weeds evaluated were annual smartweed, biennial wormwood, Canada thistle, cocklebur, common lambsquarters, devil s claw, kochia, lanceleaf sage, marshelder, nightshade, Palmer amaranth, puncturevine, redroot pigweed, Russian thistle, common ragweed, giant
ragweed, water hemp, wild buckwheat, wild mustard, wild sunflower, wollyleaf bursage, barnyardgrass, downy brome, field sandbur, green foxtail, yellow foxtail, quackgrass, volunteer grain, and wild oats. Weeds were assessed as 0, none; 1, light (scattered, up to 1 plant per 3 ft of 30 inch row); 2, moderate (1 plant per 1 ft of 30 inch row or 3 plants for grassy weeds); and 3, heavy (more than 1 plant per 1 ft of 30 inch row or over 3 for grassy weeds). Data was entered on the same data recording form used to record plant population, yield, and the major yieldlimiting factor. The weed data is published as a separate report. Diseases surveyed included Sclerotinia (wilt, head rot, mid stalk rot), Phomopsis, Rhizopus head rot, downy mildew, red rust, white rust, charcoal rot, and Verticillium. Rust was assessed for severity (percent leaf area infected) using rust assessment illustrations. All other diseases were assessed for incidence (percent infected plants). Data on lodging also was assessed. Fifty plants in three groups of 17, 17 and 16 plants were examined to make disease and lodging assessments. Data was entered on a data recording form for disease and lodging. This data is published as a separate report. Midge and bird damage each was assessed using separate sets of damage assessment illustrations. Assessments were made for the field edge and also for the interior of each field. Data also was recorded on percent of heads with webbing and on percent of plants infested with the spotted sunflower stem weevil and the long-horned beetle. Seed samples from the edge of the field and the interior were taken for analysis in the USDA sunflower insect laboratory in Fargo, ND to determine insect injury from seed weevil, banded sunflower moth, sunflower moth, and brown spot (confection only). All field data was entered on a data recording form for bird and insect damage. This data is published as a separate report. One person on each team served as recorder. That person copied the data from the three data recording forms to a master summary sheet containing all data from each field. This master summary sheet was later used for data entry onto a data spreadsheet for each team. Data from each team was transmitted electronically to Max Dietrich at the National Sunflower Association, to the USDA sunflower insect laboratory and to Art Lamey to develop master spreadsheets for each state and for the entire survey. Each state s master spreadsheet was transmitted to John Nowatzki, North Dakota State University, for construction of GIS maps. Results. All States. A total of 477 fields were surveyed across eight states. The percent of oilseed fields surveyed was as high as 97% in Kansas, 96% in South Dakota and 81% in North Dakota. The percent of confection fields surveyed was as high as 67% in Texas and 50% in Minnesota (Table 1). Estimated yields and plant populations. State average yield estimates ranged from 1,894 lb/a in Minnesota and 1,647 lb/a in North Dakota to less than 1,000 lb/a in some of the High Plains states adversely affected by drought. In general, average plant populations tended to mirror average yields between states, with plant populations as high as 16,908 plants per acre in Minnesota and 15,933 in North Dakota (Table 1). Row spacing. The majority of fields were planted with a row spacing greater than 20 inches in all states but Texas, where 100% of fields surveyed were planted with a row spacing less than 20
inches. The narrow row spacing in Texas conformed to the row spacing used for cotton. In North Dakota, 30% of fields surveyed had narrow row spacing (Table 2). Table 1. Fields surveyed, sunflower class, yield and plant population averages in each state in 2002. State No. Fields Surveyed Oilseed Confection Estimated Yield, lb/a Plant Population/A Colorado 19 68 32 672 6,167 Kansas 31 97 3 918 10,900 Minnesota 6 50 50 1,894 16,908 Missouri 1 100 0 1,429 18,641 Nebraska 12 75 25 744 10,911 North Dakota 265 81 19 1,647 15,933 South Dakota 131 96 4 1,124 12,754 Texas 12 33 67 1,019 11,732 Tillage practices. No till was used in 58% of Kansas fields and 50% of South Dakota fields. Minimum till was used in 75% of Nebraska fields and 58% of Colorado fields. Conventional till was used in 100% of Minnesota fields, 92% of Texas fields and 62% of North Dakota fields (Table 2). Table 2. Row spacing and tillage practices in each state in 2002. and Row Spacing and Tillage Practices State < 20 Inches >20 Inches No Till Minimum Conventional Colorado 5 95 32 58 10 Kansas 0 100 58 26 16 Minnesota 0 100 0 0 100 Missouri 0 100 0 100 0 Nebraska 0 100 17 75 8 North Dakota 30 70 11 27 62 South Dakota 15 85 50 33 17 Texas 100 0 8 0 92 Yield-limiting factors. The number one yield-limiting factor had a common thread in some of the drought-stricken states, where drought was the worst yield-limiting factor in 84% of Colorado fields surveyed, 71% of Kansas fields, 60% of South Dakota fields and 33% of Nebraska fields. Plant population was the number one yield-limiting factor in 50% of Nebraska fields surveyed, 42% of Texas fields, 33% of Minnesota fields, 21% of South Dakota fields and 18% of North Dakota fields (Table 3). Inadequate early season soil moisture may have contributed to poor plant populations in Texas, Nebraska, and South Dakota. Yields were low in Colorado, Kansas, Nebraska, South Dakota and Texas, states with drought or plant population problems (Table 1). Plow pans (root-restricting soil compaction zone) were the number one yield-limiting factor in 17% of Texas fields surveyed (Table 3). Results. North Dakota Crop Reporting Districts. There were 265 fields surveyed, with the greatest number of surveyed fields in the central and north central crop reporting districts, with
56 and 51 fields, respectively. Oilseed sunflower comprised 100% of the fields surveyed in the south central, northwest and southwest districts, followed by 93% in the west central. The greatest percentage of confection sunflower was planted in the northeast, with 36% of surveyed fields planted to confection sunflower, and in the southeast, with 33% (Table 4). Table 3. Number one yield-limiting factors in each state in 2002. Yield-limiting Factor 0 1 2 3 4 5 6 7 8 9 10 11 12 State ---------- Surveyed ---------- Colorado 0 0 0 84 0 0 0 0 5 0 5 5 0 Kansas 5 0 0 71 0 0 0 10 0 0 6 3 3 Minnesota 33 0 0 0 0 0 0 0 0 0 33 33 0 Missouri 0 0 0 0 0 0 0 0 0 0 100 0 0 Nebraska 0 0 0 33 0 0 0 0 0 17 50 0 0 North Dakota 15 8 18 13 2 2 0 2 5 2 18 14 0 South Dakota 2 5 2 60 0 0 0 4 0 1 21 7 0 Texas 17 0 0 8 0 8 0 0 0 0 42 8 17 0 = no problem 4 = drown-outs 8 = lodging 12 = plow pans 1 = birds 5 = hail 9 = plant spacing 2 = disease 6 = herbicide damage 10 = population 3 = drought 7 = insects 11 = weeds Estimated yields and plant populations. The estimated average yield ranged from a high of 2,199 lb/a in the northwest district to a low of 1,072 lb/a in the southwest district. Average plant populations varied from 20,643 plants per acre in the west central district to 14,141 in the central district. There was not as clear a relationship between plant population and yield in the North Dakota districts as there was between the states in the survey. However, the states with the lowest average yields had plant populations of 6,000-10,000 or 11,000. Perhaps most plant populations in North Dakota were not limiting factors (Table 4). In addition, drought was a major yield-limiting factor in the southwest district, as shown in Table 6. Table 4. Fields surveyed, sunflower class, yield and plant population averages in all nine of North Dakota s crop reporting districts in 2002. District No. Fields Surveyed Oilseed Confection Estimated Yield, lb/a Plant Population/A Northeast 33 64 36 1,464 15,128 East Central 18 72 28 1,477 16,006 Southeast 24 67 33 1,549 15,867 North Central 51 75 25 1,677 14,746 Central 56 79 21 1,684 14,141 South Central 35 100 0 1,599 19,126 Northwest 24 100 0 2,199 16,990 West Central 14 93 7 1,794 20,643 Southwest 10 100 0 1,072 14,410
Row spacing. The most common row spacing in most crop reporting districts was greater than 20 inches, with 91% of fields surveyed in the northeast and central districts having a row spacing of greater than 20 inches, followed by the east central with 83%, and the southeast and west central with 71%. A row spacing of less than 20 inches was used in 70% of the surveyed fields in the southwest district, followed by 63% in the northwest and 51% in the south central (Table 5). Tillage practices. Conventional till was the most common type of tillage, with 95% of surveyed fields in the central district receiving conventional till, followed by 86% in the west central, 76% in the northeast and 72% in the east central. Minimum till was used in 59% of surveyed fields in the northwest district, 46% in the south central and 40% in the southwest. No till was used in 50% of surveyed fields in the southwest district. Tillage in the north central district was rather evenly divided with 25% of surveyed fields receiving no-till, 30% minimum till and 45% conventional till (Table 5). Table 5. Row spacing and tillage practices in all nine of North Dakota s crop reporting districts in 2002. & Row Spacing and Tillage Practices District < 20 Inches >20 Inches No Till Minimum Conventional Northeast 9 91 3 21 76 East Central 17 83 0 28 72 Southeast 29 71 4 38 58 North Central 35 65 25 30 45 Central 9 91 2 3 95 South Central 51 49 14 46 40 Northwest 63 37 8 59 33 West Central 29 71 7 7 86 Southwest 70 30 50 40 10 Yield-limiting factors. No yield-limiting factors were reported in 50% of surveyed fields in the northwest district and 36% in the west central. Birds were the number one yield-limiting factor in 17% of east central district fields surveyed. Disease was the number one yield-limiting factor in 50% of surveyed fields in the east central district and 33% in the northeast. Drought was the number one yield-limiting factor in 80% of surveyed fields in the southwest district, 38% in the southeast, 34% in the south central and 29% in the west central districts. The high percentage of surveyed fields in the southwest district with drought as the major yield limiting factor corresponds to the yield data (Table 4), since this was the district with the lowest average estimated yields. Plant population was the number one yield-limiting factor in 38% of surveyed fields in the southeast district and 30% in the central district. Weeds were the number one yieldlimiting factor in 29% of surveyed fields in the north central district (Table 6). Results. South Dakota Crop Reporting Districts. There were 131 fields surveyed, with the greatest number of surveyed fields in the central crop reporting district, with 57 fields. Oilseed sunflower comprised 100% of the surveyed fields in the south central, northwest, west central and southwest districts, as well as the majority in the other two districts where sunflower was
surveyed. There was no survey in the three eastern districts. Only 8% of surveyed fields in the north central and 5% in the central district were planted to confection sunflower (Table 7). Table 6. Number one yield-limiting factors in all nine of North Dakota Crop Reporting Districts in 2002. Yield-limiting Factor 0 1 2 3 4 5 6 7 8 9 10 11 District ---------- Surveyed ---------- Northeast 5 13 33 0 5 0 0 3 5 0 13 8 East Central 0 17 50 0 11 0 0 0 0 6 11 6 Southeast 0 0 0 38 0 0 0 0 0 8 38 17 North Central 14 8 16 4 0 4 0 0 8 4 14 29 Central 21 7 23 0 2 2 0 0 2 0 30 13 South Central 9 9 3 34 0 3 0 6 11 0 14 11 Northwest 50 8 17 0 0 8 4 0 4 0 4 4 West Central 36 0 0 29 7 0 0 7 0 0 14 7 Southwest 0 10 0 80 0 0 0 0 0 10 0 0 State Average 15 8 18 13 2 2 0 2 5 2 18 14 0 = no problem 4 = drown-outs 8 = lodging 1 = birds 5 = hail 9 = plant spacing 2 = disease 6 = herbicide damage 10 = population 3 = drought 7 = insects 11 = weeds Estimated yields and plant populations. The estimated average yield ranged from 1,379 lb/a in the west central district to 839 lb/a in the south central. Average plant populations varied from 15,188 lb/a in the west central district to 11,625 in the southwest (Table 7). Table 7. Fields surveyed, sunflower class, yield and plant population averages in six of South Dakota s crop reporting districts in 2002. District No. Fields Surveyed Oilseed Confection Estimated Yield, lb/a Plant Population/A North Central 26 92 8 1,322 13,346 Central 57 95 5 1,123 11,982 South Central 27 100 0 839 12,692 Northwest 9 100 0 1,125 14,467 West Central 8 100 0 1,379 15,188 Southwest 4 100 0 1,248 11,625 Row spacing. Most surveyed fields in the majority of districts were planted with a row spacing greater than 20 inches. There were 100% of surveyed fields in the south central and southwest districts with a row spacing greater than 20 inches, followed by 89% in the central, 81% in the north central and 56% in the northwest. In contrast, 63% of surveyed fields in the west central district were planted with a row spacing less than 20 inches (Table 8). Tillage practices. No till was commonly used, with 100% of surveyed fields in the southwest planted to no till, followed by 58% in the north central, 56% in the northwest and 52% in the
south central. Minimum till was used on 63% of surveyed fields in the west central district. Tillage practices were fairly evenly divided in the central district, with 42% receiving no till, 28% minimum till and 30% conventional till (Table 8). Table 8. Row spacing and tillage practices in six of South Dakota s crop reporting districts in 2002. & Row Spacing and Tillage Practices District < 20 Inches >20 Inches No Till Minimum Conventional North Central 19 81 58 31 11 Central 11 89 42 28 30 South Central 0 100 52 37 11 Northwest 44 56 56 44 0 West Central 63 37 37 63 0 Southwest 0 100 100 0 0 Yield-limiting factors. The number one yield-limiting factor was drought in five of six surveyed districts. Drought was the number one yield-limiting factor in 100% of surveyed fields in the west central district, 93% of the south central, 75% of the southwest, 67% of the northwest and 65% of the central district. Drought was not a yield-limiting factor in the north central district, but plant population was a yield-limiting factor in 42% of surveyed fields in that district. Plant population also was a yield-limiting factor in 25% of surveyed fields in the southwest district and 23% in the central district. Since drought was the most common yield-limiting factor in the central and southwest districts, plant population as a yield-limiting factor in these same districts could be related to inadequate soil moisture during crop emergence and stand establishment. Weeds were a yield-limiting factor in 19% of surveyed fields in the north central district (Table 9). Table 9. Number one yield-limiting factors in six of South Dakota Crop Reporting Districts in 2002. Yield-limiting Factor 0 1 2 3 4 5 6 7 8 9 10 11 District ---------- Surveyed ---------- North Central 8 12 8 0 0 0 0 8 0 4 42 19 Central 0 2 0 65 0 0 0 4 0 0 23 7 South Central 0 4 0 93 0 0 0 0 0 0 4 0 Northwest 0 11 0 67 0 0 0 11 0 0 11 0 West Central 0 0 0 100 0 0 0 0 0 0 0 0 Southwest 0 0 0 75 0 0 0 0 0 0 25 0 State Average 2 5 2 60 0 0 0 4 0 1 21 7 0 = no problem 4 = drown-outs 8 = lodging 1 = birds 5 = hail 9 = plant spacing 2 = disease 6 = herbicide damage 10 = population 3 = drought 7 = insects 11 = weeds
Discussion. The 2001 survey was conducted only in North Dakota and South Dakota. The number of fields surveyed in those states in 2001 was similar to the number surveyed in 2002. The percent of surveyed fields planted to confection sunflower was approximately the same for both years in South Dakota, but decreased in North Dakota from 24% of surveyed fields in 2001 to 19% in 2002. Average estimated yields in North Dakota increased slightly from 1,568 lb/a in 2001 to 1,647 lb/a in 2002. Average estimated yields in South Dakota, however, decreased from 1,408 lb/a in 2001 to 1,124 lb/a in 2002. This drop in estimated yield in 2002 may be due to drought problems in South Dakota with drought a yield-limiting factor in 60% of fields surveyed and plant population a yield limiting factor in 21%. It is likely that inadequate early season soil moisture may have been responsible for plant population problems. Yield-limiting factors were not a part of the survey in 2001, so no comparison is possible. Row spacing in most fields surveyed was greater than 20 inches in both states and both years, even though the means of measurement was different in 2001 and 2002. In 2001, data was recorded on fields that were solid seeded and those that were row seeded. In 2002 data was recorded on fields with row spacing greater or less than 20 inches. For purposes of comparison between years, solid seeding is compared to and row spacing of less than 20 inches. Conventional tillage in North Dakota decreased slightly from 76% of surveyed fields in 2001 to 62% in 2002, minimum tillage increased from 17% in 2001 to 27% in 2002 and no till increased from 7% in 2001 to 11% in 2002. Conventional tillage in South Dakota decreased considerably from 49% of surveyed fields in 2001 to 17% in 2002, minimum till increased from 20% in 2001 to 33% in 2002 and no till increased from 31% in 2001 to 50% in 2002. Although the reduction in use of conventional tillage may represent a trend, it also may reflect producer efforts to conserve soil moisture in areas with limited soil moisture at planting time. Literature Cited 1. Lamey, Arthur, Max Dietrich and Martin Draper. 2002. Sunflower crop survey in North Dakota and South Dakota. In Proceedings of the 24 th Sunflower Research Workshop, January 17-18, 2002, pages 1-11.