Grain legumes need water to grow, but different types use water differently. Cool season legumes produce more yield with less water than warm season ones. Some legumes have traits that help them use water efficiently, like adjusting how much water they take in based on the season. Certain traits, like improved photosynthesis and root length, can help legumes grow better even when there's not much water. Legumes with conservative traits use less water, which is good during long dry periods, while those with profligate traits can take advantage of short bursts of water. Overall, understanding how legumes use water can help farmers grow more crops with less water.