Moderate to severe drought stress afflicted much of Wisconsin’s soybean crop in 2007. In soybean there are two growth periods for which soil moisture is critical for optimum growth and development: at planting and during the reproductive stages from bloom through pod fill. The time period from stand establishment to bloom is not as critical. Drought stress during this time period will often shorten internodes; however yield loss rarely occurs. In Wisconsin the main reproductive growth in soybean occurs from early July to mid-September. Soybean in this phase use about 1/4 to 1/3 inch of water per day. Lack of sufficient water can cause flowers and young pods to abort reducing the number of seeds per plant. Also, soybean plants reduce the size of their leaf pore openings to reduce the loss of water vapor. This also reduces the intake of carbon dioxide and the manufacturing of photosynthates which slows plant growth. When normal soil moisture returns, normal growth is resumed. This ability to reduce metabolic activity allows plants to tolerate dry spells without dying or harming their ability to resume growth when normal moisture returns.