Legume crops can help improve soil quality and wheat crop yields. In this study, researchers compared different legume species to see how they affected soil nitrogen levels and subsequent wheat growth. They found that legumes like alfalfa and hairy vetch can increase soil nitrogen levels, leading to better wheat yields without the need for as much fertilizer. Wheat grown after legume crops had similar or better yields compared to fallow or heavily fertilized wheat fields. This suggests that using legume crops as green manure can be a beneficial alternative to leaving fields fallow in areas with higher moisture levels.