Cut and Post-Cut Herbage Management Affects Berseem Clover Seed Yield

The seed yield of berseem clover (Trifolium alexandrinum L.) is usually obtained from regrowth after forage utilization. In stockless, cereal-growing, or specialized seed farms the forage is not needed and the mowed herbage is seldom marketable. Three different experiments were conducted in a Mediterranean environment to evaluate the effect of returning the cut biomass to the soil/crop on the regrowth, seed yield, and seed quality of berseem clover. Different forms of cut and post-cut management were examined, in which the time of cutting, the amount of biomass returned to the crop/soil, and the size of the returned material (unchopped or chopped) all varied. In addition, the effect of the berseem management on the grain yield and N content of a subsequent durum wheat (Triticum durum Desf.) crop was evaluated. The study showed that when cutting takes place during the early spring, removing and returning the herbage both result in similar seed yields but when cutting takes place later it is necessary to chop the herbage to eliminate or strongly attenuate the negative effects of mulching on seed yield. In farms in which it is not convenient or possible to use the cut herbage, returning the herbage to the crop/soil (without detrimental effects on seed yield) would increase N availability for subsequent non-legume crops. This option appears to be particularly relevant to organic farming.