Corn Growth as Affected by Excess Soil Water

In a two-year study, com was subjected to controlled flooding during various physiological stages of growth by using specially constructed isolated field plots to determine how growth and grain yield were affected by excess soil water. Com was most susceptible to flooding at the early-vegetative stage (36 days after planting) with maximum reductions in plant-canopy height, dry-matter production, and grain yield. Two-year averages of the crop susceptibility (CS) factors calculated from the yield data were 0.64, 0.44, 0.15, and 0.19 for early-vegetative, late-vegetative, flowering, and yield-formation stages of growth, respectively. The SDI concept was tested by comparing the relative yield-SDI relationships for a nearby area with naturally fluctuating water tables using CS values obtained in this study. The SDI models indicated a linear decrease in the relative yield with increasing wetness (SDI values), but the best-fit regression lines of the yield-SDI data for the undrained area differed considerably between years.