Influence of changes of climate on the productivity of pratal and steppe vegetation in the Forest-steppe area of Ukraine

The influence of the climate change on the agro-climatic growth conditions, development and formation of productivity of meadow and steppe vegetation in the forest-steppe zone of Ukraine for three periods has been studied: 2021–2030, 2031–2040, 2041–2050. The calculations of the expected conditions have been performed according to the climate change scenarios RCP4.5 and RCP8.5. The paper provides an assessment of the agro-climatic conditions for the formation of productivity of meadow and steppe vegetation in the current global warming and further climate change conditions until 2050. The assessment has been performed by comparing the average long-term agro-climatic indicators (1980–2010) of the productivity of wild phytocenoses with the same indicators for the future over decades. The calculations of both average long-term productivity of grasses and productivity of grasses in the conditions of climate change are executed according to four types of productivity: potential productivity which in case of optimum maintenance of plants with heat, moisture and mineral food is defined by solar radiation; meteorologically possible yield, which is provided by the temperature regime and the regime of humidification of the territory; really possible yield capacity, which is provided by the natural fertility of the soil; actual yield capacity in the natural conditions. Key words: meadow, steppe vegetation, productivity, humus balance, photosynthetic potential, agroecological categories of yields, climate change.