Justification of productivity of lucerne in long-term use of grass biomass in the context of climate change

Abstract

Goal. To determine the influence of sowing date and hydrothermal resources on the processes of growth, development, and formation of productivity of agrophytocenoses of lucerne in the first year of life. Methods. Agrotechnical measures of cultivation of lucerne were common for the conditions of right Bank Forest-Steppe, which included the traditional tillage. Results. In the year of sowing plants of lucerne revealed the photoperiodic response to the adverse climatic conditions of the growing season. The change of the photoperiod in plants of lucerne testified to the passing of microstages of growth and development and was adjusted by the day length and sowing time regardless of temperature and moisture. They determined that for the period of study lucerne adapted to climate change and provided the high-performance feed for early spring sowing. The intensive use of lucerne within 3 years provided the highest yield of leaf-stem mass — 47,03 t/ha, as well as yield of dry matter — 11.09, crude protein — 2,07 t/ha, and accumulated gross energy — 204,72 and metabolizable energy — 104,52 GJ/ha, while recommended summer term of sowing on the indicators was lower, respectively by 9.1; 11,5; 13,1; 12.2 and 11.7%. Conclusions. It was determined that in the year of sowing on gray forest soils of Forest-Steppe right Bank lucerne reached the stage of 61–62 (VVSN) at day length of 14,53–16,12 hours, and phase 49 (VVSN) — at 12,48 hours. Forage productivity of lucerne was influenced by hydrothermal conditions and sowing dates. Genetic potential of culture was maximally implemented in the 3rd year of cultivation with sufficient watering during the growing season.