Wheat-Soybean Relay Intercropping: Proof of Concept
Question: How does relay intercropped wheat-soybean compare to standard soybean and double-crop wheat-soybean?
Responsible graduate student: Yuri Gross (yuribgross@ksu.edu)
Locations
Ottawa, Kansas
Manhattan, Kansas
Scandia, Kansas
Factors Evaluated
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System: standard soybean, standard wheat, relay intercropped wheat-soybean, double cropped wheat-soybean
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Soybean planting date: April/May vs May/June (relay and standard)
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Soybean genotype: 3.7 MG vs 4.2 MG
Measurements
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Yield (wheat and soybean)
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Crop growth (wheat and soybean biomass at 3+ season timepoints, plant height, node number, etc.)
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Crop development (wheat and soybean stage progression)
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Light (canopy coverage and light interception)
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Weeds (density, species, and stage)
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Soil characterization
Preliminary Results (2024-2025 season)
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25% less wheat yielded only 10% less (good compensation potential with tillers in edge rows along gaps)
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Relay soybean yields were equal or better than double-crop yields
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Relay soybean yields were reduced compared to monocrop soybean yields
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Earlier planting dates were best for relay and monocrop soybeans
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Weed control by wheat was noticeable (added competition could reduce herbicide needs)
2025 yield results are shown below. Yields are the average of replicated plots at each location. Yields with the same letter indicate that there was not a significant difference for that crop x location combination. (For example, all soybean yields were statistically similar in Ottawa, regardless of system - all "a"s)
Location | Treatment | Yield (bu/ac) | Yield (bu/ac) |
|---|---|---|---|
Soybean | Wheat | ||
Manhattan | Monocrop soybean | 58.4 a | - |
Relay intercropping | 49.8 b | 44.5 (skip) b | |
Double cropping | 31.1 c | 49.1 (solid) a | |
Ottawa | Monocrop soybean | 58.0 a | - |
Relay intercropping | 54.5 a | 74.4 (skip) b | |
Double cropping | 52.1 a | 82.8 (solid) a | |
Scandia | Monocrop soybean | 44.2 a | - |
Relay intercropping | 28.0 b | 34.4 (skip) b | |
Double cropping | 19.5 c | 42.6 (solid) a |
Funding Acknowledgement
This research is generously funded by a multiregional Soybean Checkoff grant and North Central SARE project GNC25-408.
