Modeling of sunflower’s productivity under future climate changes in Ukraine considering the scenarios of RCP anthropogenic impact

Abstract

Climate change is one of the major global issues. Climate is one of the most significant factors determining the level of crop yields, including sunflower crops. Currently the sunflower planting acreage in Ukraine has already reached its maximum value. Therefore the potential for increasing sunflower production should be aimed at increasing its yield. To assess the impact of climate change on sunflower productivity the article considers modern scenarios of RCP (Representative Concentration Pathways) such as RCP 4.5 and RCP 8.5. They belong to the scenarios of medium and high levels of greenhouse gas emissions. The RCP 4.5 and RCP 8.5 scenarios cover the climatic period from 2021 to 2050. In order to conduct a comparative analysis of scenario meteorological values with previous data from the Agroclimatic Reference Book of Ukraine, the period from 1986 to 2005 was taken. It serves as a basic period for calculations. Calculations were made for the following natural and climatic zones of Ukraine: East Forest-Steppe, Northern and Southern Steppe. The article studies the influence of agroclimatic conditions on sunflower cultivation as per two interphase periods: shoots - blooming and blooming - picking maturity. Study of sunflower productivity formation was carried out using a mathematical model of the water-heat regime and sunflower productivity. The model is based on the system of equations of radiation, heat and water balances and biomass balance in vegetation cover. According to calculations a lowered temperature regime and sufficient moisture in the first half of sunflower vegetation season will favor the formation of leaves way more than during the basic period within the entire area under study. However, expected arid conditions in the second half of vegetation period will cause a very low sunflower moisture availability during this period which would lead to reduction of sunflower seeds' crop-producing power. Analysis of agroclimatic conditions during vegetation season from sunflower shoots to its picking maturity showed that implementation of both scenarios would ensure expected weather conditions to be more favorable for sunflower growing in the eastern forest-steppe zone of Ukraine. The greatest risk of sunflower crops shortfall in certain years is expected in the southern steppe zone of Ukraine and significant losses should be expected in case of scenario RCP4.5 implementation.

Keywords

• sunflower, vegetation period, climate change, agro-climatic conditions, risks of crops shortfall