THE PECULIARITIES OF WATER CONSUMPTION OF SUNFLOWER UNDER DIFFERENT CONDITIONS OF MINERAL NUTRITION

Abstract

Traditionally, sunflower has been considered an unsatisfactory predecessor for most crops of crop rotation because of the uptake of nutrients and moisture from the soil. It has recently been proved that sunflower is not a crop that intensively takes out nutrients, as far as its high consumption of macro- and micro- elements is accompanied by a compensatory return of them to the soil with after- harvest remains. Sunflower really takes out that amount of water from a meter layer of soil which has been accumulated in pre-sowing and growing periods. When there  is not enough rainfall in dry years, sunflower actively uses water supply from deeper layers and can satisfy its needs at the expense of the moisture supply from the layer of 40–200 cm by 50–60%. But in spite of weather conditions sunflower always reduces the supply of soil moisture considerably, often causing problems for successive crops and for itself as well. It is possible to improve moisture balance at the expense of reducing its nonproductive use and improving conditions for accumulating it in the soil.

In the experiments carried out in Yelanetsk district of Kherson region during the years of 2015–2016 we studied the elements of sunflower water balance depending on the level of mineral nutrition and the application of complex multifunctional chemicals. The field experiment was conducted according to a two- factor scheme: the factor A was the background of mineral nutrition(the test plot without applying fertilizers; N30P45, N60P90), and the factor B was the foliar nutrition with the chemicals (Vuksal Microplant – a micro-fertilizer of the German company Aglukon and Helafit Combi – a multifunctional chemical of the company “Helafit”, Ukraine). The experiments showed that the application of fertilizers and chemicals regulating plant growth in spite of the increase of the total water consumption (up to 7%) reduces the specific water consumption (up to 30%) and it is the evidence of economical moisture use. The chemicals increase the level of sunflower yields both independently (9–14%) and in combination with fertilizers (29– 40%). The anti-stress action of these chemicals successfully adds to a positive effect of mineral fertilizers, softens the action of unfavorable environmental factors and reduces the time of stress. If we add a fungicide effect of the chemicals (first of all Helafit Combi), then the expediency of using them separately and in combination  with mineral fertilizers is understandable.