Optimization of Cultivation of Medicago varia for Seeds
The research was aimed at the development of technological methods of cultivation (sowing dates and methods) of Medicago varia ‘Daria’ in order to form the maximum seed productivity in the forest-steppe of the Middle Volga region. The object of the research was a new promising variety of Medicago varia ‘Daria’, included in the State register of breeding achievements in three regions of the Russian Federation: the Middle Volga, Volga-Vyatka and Central Black Earth regions. The investigations were carried out on the experimental field of Penza Research Agricultural Institute in a forage crop rotation by conventional methods in 2014-2017. It was studied the effect of sowing date (May 1-10 - the control; May 20-30; June 1-10; July 1-10) and methods of sowing (drill sowing with the row-spacing of 15 cm - the control; drill sowing with the row-spacing of 30 cm; wide-row sowing with the row-spacing of 45 cm, 60 cm, and 70 cm) on the seed productivity of alfalfa. The soil of the experimental plot was leached heavy-loamy chernozem with a high content of available phosphorus and exchange potassium. Weather conditions during the years of the experiment differed substantially; the hydrothermal coefficient was 0.77 units during the period from the regrowth to the full maturation of alfalfa seed in 2015, 1.13 units during the same period of 2016, and 0.71 units in 2017. The best sowing dates for Medicago varia ‘Daria’ were the third decade of May or the first decade of June. The choice of these seeding dates allowed to harvest 208 and 270 kg/ha of seeds in the first year of use, 229 and 189 kg/ha in the second year, 39 and 34 kg/ha in the third year, respectively. On average for three years the yield was 159 and 164 kg/ha of alfalfa seeds, correspondingly. The optimal width of the row-spacing of alfalfa in the case of sowing for seed purposes is 45 cm: the yield was 284 kg/ha of seeds in the first year of use, 300 kg/ha in the second year, and 55 kg/ha in the third year. On average over three years the harvest was 213 kg/ha, which was 9.7% higher than for the drill sowing.