There is a lot of interest in seeding a legume into wheat as a nitrogen source and to add organic matter to the soil. Although many of the benefits of such legume seedings are well known, it is important that wheat growers have good information about how different legumes respond to the nitrogen levels used in wheat for top yields. However, it is becoming clear that there are certain benefits provided by legume seedlings that are not so well understood. The benefits extend beyond those attributable to the amount of nitrogen supplied by the legume biomass.
Wheat responds to increased nitrogen by increasing vigor of vegetative and reproductive growth.
This makes it more competitive with the legume, which becomes less productive at higher nitrogen levels. Therefore, the amount of nitrogen added should represent a compromise between the level needed for good wheat yields on one hand, while not crowding the legume to the point that the seeding becomes unsuccessful. Plow-down stands were poor, however, with sweet clover, California common alfalfa, and Canadian mammoth clover. High N rates produced heavy leaf and straw growth on wheat and reduced the light available for good legume seedling establishment. June clover Canad.