An analysis has been made on the characteristic values of biomass of Onobrychis viciaefolia, including weight of dry matter, ratio of green mass to dry mass, growth rate, leaf area index, rate of net assimilation, and efficiency for solar energy utilization. Based on the dynamics of various, their relationships with each other, and the effects of climatic conditions on them, it is concluded that the peak flowering period would be the best season of the grass harvest, and the key measures have been suggested...