Establishing Wheat After Soybeans in Double-Cropping1
- J. O. Sanford2
A method whereby wheat (Triticum aestivum L.) can be sown earlier would be a distinct advantage in a wheatsoybean (Glycine max (L.) Merr.) double-cropping system. ‘Abe’ wheat overseeded in standing soybeans about 1 October was compared with conventionally seeded wheat after soybean harvest (1 to 10 November). Wheat overseeded consistently outyielded the conventionally seeded wheat. The optimum seeding rate for overseeding wheat was 101 kg/ha. Overseeded wheat failed during 1 of 4 years, because the soybean canopy was only 50% closed because of late planting (15 July).
The growth regulator, 2, 3, 5-triiodobenzoic acid (TIBA) was applied to ‘Bragg’ soybeans at different growth stages to create canopies with varying degrees of closure. Plots with these different canopies were overseeded with ‘Abe’ wheat at a rate of 134 kg/ha about 1 October (when the topmost soybean leaves began to turn yellow). Emergence and yield of wheat were significantly greater when no TIBA was applied (completely closed canopy) than when TIBA was applied and the canopy was not completely closed.
Overseeding wheat in standing soybeans in double-cropping was found to be an acceptable method of establishing the wheat crop However, emergence and yields of wheat can be expected to be reduced when the soybean canopy is less than completely closed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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