Evaluating on-farm flooding impacts on soybean

Flooding is a major problem that reduces soybean [Glycine max (L.) Merr.] growth and grain yield in many areas of the USA and the world. Our objective was to identify the plant and soil characteristics associated with different flooding durations in six fields in central Ohio. The soybean plants were at the V2 and V3 stages when rainfall-induced flooding occurred. The outer perimeters of the flooded areas were mapped, using GPS (global positioning system) technology, several times during the flooding event to delineate the change of the hooded area over time. Two 9-m wide transects across the flooded area within each field were divided into plots of 9 m by 9 m according to flooding duration: no flooding, 1 to 3 d, 4 to 6 d, and 6 to 8 d, Soil and plant nutrient levels, grain yield data and grain protein and oil content were determined for each plot. The soil cation-exchange capacity (CEC), pH, P, Ca, Mn, and Zn concentrations had significant positive correlation with flooding duration. There was a significant negative correlation of flooding duration with the population, height, number of pods, and yield of soybean, There was no significant correlation of flooding duration with seed weight, oil, or protein content of the seeds. Leaf tissue Ca, Mg, B, Fe, Cu, and Al concentrations had a significant positive correlation with flooding duration, whereas lear tissue N concentration had a significant negative correlation with flooding duration.