November 28, 2000
Double-crop Buckwheat, Sunflower, and Soybean Comparison
K. Nelson, C. Bliefert, R. Smoot, J. Bryant and D. Harder
Buckwheat is an annual crop with hollow stems, white flowers (Figure
1), heart-shaped leaves, and grows from 2 to 5 ft. tall.
Figure 1. Buckwheat flowered by
21 days 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,
Figure 2. Mature buckwheat
seed 11 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.
Figure 3. Sunflower nine weeks
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
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 4. Buckwheat emerged six
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.
Figure 5. Soybean (left) and buckwheat
(right) 32 days after planting.
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.
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
at the University of Missouri-Columbia
Site maintained by people at AgEBB