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2005 Annual Report: Soybean Row Planting Width


Demonstrate a winter wheat/soybean double cropping system. Also, encourage winter wheat as a third crop which can spread weather, input and selling price risk.

Methods and Materials

Crop Management Info
Planting Date : Oct. 4, 2004 & July 5, 2005
Herbicides: Roundup
Hybrid: Truman Wheat
Wilcross 54315NRR soybeans
Insecticides: None
Population: 120 lbs/acre wheat
160,000 seeds/acre soybeans
Row Width: 9-inch wheat
30-inch soybeans

Demonstration Design
Replications: 3
Design: Randomized Block
Size: 10 X 30
Statistics: Analysis of Variance


The Truman winter wheat yielded 68 bu/acre. The soybeans yielded 21 bu/acre. The soil is a heavy gumbo soil at this location.

Recommendations for double crop winter wheat/soybeans:

  • A good stand of winter wheat reduces weed competition and keeps weeds small as the wheat matures. After wheat maturity, the weeds will be easier to control as they are smaller.
  • Weed competition may not only be from weeds but from wheat blown over during the harvest of wheat. If possible, delay the glyphosate application after the volunteer wheat has germinated and large enough to be controlled. Often, one herbicide application is all that is necessary for adequate soybean weed control.
  • Plant soybeans into moist soil. One may have to move surface soil in order to reach moist soil.
  • Use narrow rows rather than 30-inch rows when planting double crop soybeans. Research indicates a 15-20% increase in yield when moving to narrow compared to wide rows.
  • Increase seed rates of double cropped soybeans compared to normal planting rates.
  • Once soybean pods yellow, soybeans are close to maturity and yields from frost will be lessened.
  • Fertilizer applications are developed from both crops rather than a single crop.