EVALUATION OF THE PRODUCTION PROCESS OF CROPS OF PERENNIAL GRASSES IN THE EFFICIENCY OF PAR
The article presents the results of the evaluation of the production process of perennial grasses on the example of elecampane (Inula helenium L.). The modified method of calculating the efficiency of the PAR is based on taking into account the development and functioning of aboveground and underground organs and the transition of assimilates deposited in the underground phytomass from one year to another. It is established that the value of the efficiency of PAR depends on the conditions of moistening. Under favorable climatic conditions, the efficiency of the PAR of aboveground phytomass increases due to the rapid transport of assimilates from rhizomes and their use for the growth of aboveground phytomass. Under dry conditions, there is an increase in the efficiency of PAR of the underground phytomass. This ensures the maximum reduction in the costs of photosynthesis products for growth and respiration of the aboveground organs, a higher viability and increased competition under conditions of soil moisture. Higher values of the efficiency of PAR of the underground and total phytomass are characteristic of species with a combined SRS strategy, in which the R component dominates. The proposed method for calculating the efficiency of PAR on aboveground and underground phytomass over many years allows for a more accurate assessment of the ecological strategy of a species and its potential productivity, since the determination of the efficiency of PAR only on aboveground phytomass underestimates the true value of the efficiency of solar energy absorption for photosynthesis. The proposed technique is important for the development of scientific bases for improving pastures and hayfields, increasing the productivity of crops of perennial forage and medicinal herbs.