Harvest of agricultural crops depends on availability of biological properties of plants, aggregate of technological measures for plants growth, peculiarities of soil covering and weather and climate conditions, social importance of products and their economic value.
Crop capacity of spring barley depends on many factors, among which there are the most important ones such as light, heat, moisture, mineral nutrition etc. Climate changes that became particularly noticeable during the recent decade cause change of agro-climatic conditions of spring barley growing, which, in their turn, cause change of rates of crops growth, change of parameters of formation of its productivity which significantly determines the level of crop capacity.
Photosynthetic activity of plants depends mainly on supply of solar radiation as the primary source for all biological and physical processes taking place in plants. According to data of studies the role of solar radiation in plants’ life appears to be multilateral one and is determined not only by patterns of change of elements of plants’ photosynthetic activity depending on each other, but also by the influence of changes of agro-climatic and farming practices, plants’ density, standards and periods of irrigation and nutrition.
Indices of the radiation-and-temperature regime in the Steppe zone of Ukraine in the period of 1986 through 2005, as compared to the expected changes in these indices, calculated in accordance with the two climate change scenarios, RCP4,5 and RCP8,5, for the period of up to 2050, are under consideration in the paper. RCP4,5 is a scenario of stabilization of greenhouse gas emissions into the atmosphere, while RCP8.5 is the one of very high greenhouse gas emissions. To characterize the radiation and thermal resources in the Steppe zone of Ukraine in the period of 1986 through 2005 (the basic period), and the change in the period of 2021 through 2050 calculations of average long-term values for the first group of environmental factors were performed: the duration of day-time, the total daily solar radiation, the intensity of photosynthetically active radiation (PAR), the accumulated PAR, the radiation balance of the vegetation cover, and the temperature regime. The following principal agroclimatic characteristics of the temperature regime were considered: dates of stable rise of the air temperature above 0, 5, 10, 15 °C in spring and autumn, duration of the period with air temperatures above 0, 5, 10, 15 °C, the accumulated positive air temperatures for the period with air temperatures above 0, 5, 10, 15 °C, the average air temperature in January and July, and the amplitude.
It is pointed out that in the period of up to 2050, according to the calculations in both scenarios, increased indices of the radiation-and-temperature regime will be observed. The values of the radiation regime parameters will predominantly increase in late summer and early autumn. As a result of the inflow of increased accumulated solar radiation, the accumulated temperatures in the period with air temperatures above 5 °C will also rise. The expected increase in the accumulated temperatures will nevertheless not exceed 200 °C. A rise in the total temperature will contribute to better heat supply for the crops.
In work the influence of different terms of sowing on growth, development and forming of productivity of sugar beet is examined. Comparative quantitative estimation on photosynthetic activity of plants in sowing and duration of basic interphase periods at a sugar beet is given.
The article considers parameters of heat and radiation regime within natural and climatic zones of Ukraine for the period of 1986 – 2005 in comparison with their expected changes calculated with regard to two scenarios of climate change: RCP4,5 and RCP8,5 for the period up to 2050. It is noted that during the period up to 2050 there will be an increase of parameters of radiation and thermal regime observed within all natural and climatic zones of Ukraine based on the calculations related to both scenarios. Increase of values of parameters of radiation regime will be observed mainly in the second half of summer and in early autumn. Due to increased amounts of solar radiation in some regions of Ukraine amount of temperatures during the period in question will increase as well with air temperatures exceeding 5 ° C. However expected increase of amount of temperatures will not exceed 200° C. Increase of amount of temperatures will promote better heat supply for agricultural crops.
The influence of agrometeorological conditions on photosynthetic productivity of soya is under consideration in the paper. Net productivity of the photosynthesis of soya plants was determined by interphase periods of development.
The results of numeral experiments are resulted and quantitative estimation of influencing of different terms of sowing on intensity of photosynthetic activity of plans of culture of beans in the basic natural-climatic areas of Ukraine is given.
In the work it is examined the influence of agrometeorological terms on forming of productivity of sugar beet at
different terms of sowing. Comparative quantitative estimation is given to photosynthetic activity of plants in
sowing and productivity of sugar beet at different agrometeorological terms.