University of Missouri-Columbia
MU Greenley Memorial
Agricultural Experiment Station
College of Agriculture, Food and Natural Resources

Driving directions
Novelty, Knox County

Field Day
* August 5th, 2014




Variety Testing


Contact us
Kelly Nelson
P.O. Box 126
Novelty, MO 63460
Phone: 660-739-4410

November 28, 2000

Double-crop Buckwheat, Sunflower, and Soybean Comparison

K. Nelson, C. Bliefert, R. Smoot, J. Bryant and D. Harder

Figure 1. Buckwheat flowered by
21 days after planting.
Buckwheat is an annual crop with hollow stems, white flowers (Figure 1), heart-shaped leaves, and grows from 2 to 5 ft. tall.

Figure 2. Mature buckwheat
seed 11 weeks after planting.
Buckwheat grain (Figure 2) is commonly used in pancakes and noodles. Wheat acres in Northeast Missouri have been declining in the last decade due to low profitability and risk associated with double-crop soybean. However, crops with rapid growth such as buckwheat could add value and reduce risk associated with double-crop production systems. Farmers in Northern Missouri were offered contracts in July, 2000 to grow buckwheat through Minn-Dak Growers, Ltd. Previous research provided information on alternative crops for farmers in Missouri utilizing double-crop production systems (Pullins et al, 1997).

Figure 3. Sunflower nine weeks
after planting.
In this research, buckwheat and sunflower (Figure 3) grown in central and southern Missouri demonstrated the most competitive returns (Pullins et al, 1997). Recently, sunflower production has made another surge in Missouri (Fairchild, 2000). However, availability of crushing plants has been a major limiting factor preventing sunflower production.

Two buckwheat varieties were sold to Missouri farmers in July; however, limited information on yield was available. This study was designed to compare grain yield of Koto and Koban buckwheat varieties and compare cost-effective alternatives to double-crop soybean in Northeast Missouri. This research was conducted to provide additional information to producers on the economic returns of double-crop buckwheat and sunflower compared to soybean.

Soybean, buckwheat, and sunflower were planted in replicated 10 by 40 ft plots with a Great Plains no-till drill on July 10 at 200,000 seeds/acre, July 14 at 58 lbs/acre, and July 14 at 5 lbs/acre, respectively. Final stands were recorded for each crop (Table 1). Soil was a silty clay loam with 3% organic matter, 6.7 pH, and high phosphorus and potassium. Buckwheat and sunflower plots were fertilized with 50 and 80 lbs of ammonium nitrate, respectively. All plots were treated with Select (clethodim) at 8 oz/acre plus COC at 1 qt/acre on July 28 to avoid competition with volunteer wheat. Soybean required an additional Roundup Ultra (glyphosate) treatment at 1 qt/acre plus ammonium sulfate at 17 lbs/100 gal. on August 21 for control of tall waterhemp, Venice mallow, and volunteer wheat. Plots were harvested with a small plot combine and moisture adjusted to 13, 16, and 9% for soybean, buckwheat, and sunflower, respectively.

Figure 4. Buckwheat emerged six
days after planting.
An economic analysis evaluated gross margins for the double-crop options. Gross receipts were calculated as the product of crop yield and assumed market price of $5.00/bu, $0.105/lb, and $0.09/lb for soybean, buckwheat, and sunflower, respectively. Weed management cost for soybean was $12.00/acre. Seed cost was $29.60, $16.24, and $18.75/acre for soybean, buckwheat, and sunflower, respectively. The gross margin was calculated as the difference between gross receipts and weed management, seed, and fertilizer cost.

Figure 5. Soybean (left) and buckwheat
(right) 32 days after planting.
Buckwheat (Figure 4) emerged quickly and was more competitive with weeds compared with soybean (Figure 5). Height (Table 1) and early canopy closure (visual observation) of buckwheat and sunflower compared to soybean helped reduce late germinating weed and volunteer wheat growth.

Grain yield and gross margin of Koto was greater than Koban (Table 1). This could be due to less lodging of Koto compared with Koban. Soybean grain yield was 8.5 bu/acre. Gross margins of double- cropped buckwheat or sunflower were $70.40 to $115.10/acre greater than soybean in this study. The sunflower variety in this research was an oil variety; however, there are no crushing plants available for sunflowers in Northeast Missouri.

Table 1. Double-crop soybean, buckwheat, and sunflower population, lodging, height, yield, and gross margins following wheat.

Double-crop Cultivar Population Height Lodging Yield Gross margin
plants/acre in. % $/acre
Soybean AG3701 143,000 24 0 8.5 bu/acre 1.10
Buckwheat Koto 580,000 34 43 1100 lbs/acre 87.70
Buckwheat Koban 570,000 28 74 945 lbs/acre 71.50
Sunflower SF270 21,000 67 0 1704 lbs/acre 116.20
LSD (p<0.05) 4 8 26.70

In this research, soybean were planted as soon as buckwheat contracts were available to producers. In other double-crop soybean research at the Greenley Research Center, soybean planted on June 30, 2000 yielded from 13 to 28 bu/acre which could increase gross margins from $23 to 98/acre depending on the weed management system. One of the major challenges for buckwheat and sunflower double-crops is marketing. Additional information on these and other crops is available from your local extension agronomist. In Northeast Missouri, contact Dr. Leon McIntyre (Linn Co.), Dr. Alix Carpenter (Marion Co.), or Eldon Dilworth (Knox Co.).

Fairchild, S. 2000. Something new under the sun: A case for
sunflowers. Missouri Ruralist. October: 12-18.

Pullins, E.E., R.L. Myers, and H.C. Minor. 1997. Alternative crops
in double-crop systems for Missouri. Univ. Ext., Univ. of Missouri-Columbia, G 4090.

The Missouri Agricultural Experiment Station is the research arm of the
College of Agriculture, Food and Natural Resources
at the University of Missouri-Columbia

Site maintained by people at AgEBB