Emma Matcham and Shawn P. Conley, Department of Agronomy, University of Wisconsin-Madison
As soybean plants grow and develop their transpiration increases, and soil water depletion happens faster. Soybean vegetative growth only require 0.7 inches of water per week, but flowering (stages R1 and R2) plants need twice that amount (1.4 inches of water per week). Once bean pods are elongating (R3), soybean water use increases to 1.4-1.75 inches of water per week. A soybean crop uses more water and is more likely to have lower yields due to water deficit during the pod-fill stage than they are earlier in the season.
Read the full article at the Coolbean website.
https://coolbean.info/2020/06/16/soybean-irrigation-reproductive-growth/