Furrow irrigating soybean prior to a large, unexpected rainfall event can reduce nitrogen fixation and crop yield. The objective of this study was to evaluate the tolerance of soybean cultivars to waterlogged alluvial soils. Five cultivars were selected, which showed a range of tolerances to excessive soil water. Flood duration and flood timing experiments were conducted on clay and silt loam soils. Main plots were flooding duration and flood timing and subplots were soybean cultivars. Most cultivars were able to withstand flooding for 48-96 h without crop injury. Cultivars flooded during the V5 growth stage suffered the least amount of yield loss. The greatest yield losses from flooding occurred at the R5 growth stage. Soybean yields from cultivars flooded at R5 were reduced by 20-39% compared to non-flooded checks. Pioneer 94B73 (cv.) had no significant change in yield from flooding for 192 h at any of the three growth stages, compared to non-flooded controls.
