Due to the significance of the tasks of resource and energy saving, particular importance in field feed production of the Middle Urals should be given to perennial grasses. A birds-foot trefoil (Lotus corniculatus L.) is of interest as a perennial legume plant that can grow on acidic infertile soils (pH 4.2-4.5) which has high winter hardiness and drought resistance. In 2011-2017 the study of the photosynthetic activity of birds-foot trefoil and the formation of its yield in dependence to different cover crops, methods of sowing and seeding rates, was carried out. Depending on studied methods the fodder productivity varied from 4.47 to 5.21 t / ha dry matter for four years of use on the average. By the flowering phase the largest leaf area (41.3-46.2 thousand m2/ha) was formed by a bird's-foot trefoil sown without a cover and under the cover of spring wheat and oats with the sowing rate of 6 million pcs. for wide-row sowing and 8 million pcs. of germinating seeds/ha for the ordinary row sowing. Sowing of the bird's-foot trefoil without cover and under the cover of spring wheat promoted the intensive development of photosynthetic potential -3.62-3.78 million m2 per day/ha. However, an increase in the leaf area in the variant with sowing a birds-foot trefoil without a cover contributed to a decrease in the net photosynthesis productivity to 3.9 g/m2. The highest net photosynthesis productivity (5.1-5.6 g / m2 per day), as well as the collection of dry mass in the first mowing (1.75-1.84 t / ha) was provided by a birds-foot trefoil sown under the cover of spring wheat and oats with a sowing rate of 7 million pcs. of germinating seed / ha in a wide-row sowing, and with a norm of 9-10 million pcs. of germinating seeds / ha in the ordinary row sowing. The analysis of the obtained data showed that the optimal structure of crops emerged in segregated variants with such indicators: the stalk density of bird's-foot trefoil is 745-803 pcs. / m2, the plants height is 37-39 cm, the foliage is 46-47%.