Formation features of the water-thermal regime of drained soils under climate change

Abstract

Goal. To reveal the peculiarities of the formation of the water-thermal regime of drained soils and the possibility of integrated management of water-thermal regime of the root layer of soil with the aim to create optimal conditions for growing crops in changing climate. Methods. Analysis and synthesis of knowledge regarding the influence of the thermal regime of soil on crop production on drained lands, empirical — experiment and observation on experimental plots of irrigation and drainage systems, mathematical modeling and experimental data processing. Results. They suggest that the temperature regime of drained soils is closely dependent on the water regime. The results of field investigations showed that with depth the temperature regime of the soil is closely dependent on the groundwater level. Most of all, this dependence is shown since the depth of 20 cm. In the upper layer (up to 5 cm) quite significant impact is observed of the temperature of the surface layer of air. The difference in soil temperature at depths of 5 and 20 cm in some periods reaches 3°C (at the temperature of the groundwater from 9.5 to 10.3°C), and the greatest temperature fluctuations in the upper soil layer are observed at the depth of 5 cm. For the lower soil horizons (30–50 cm) influence of temperature of the surface layer of air is greatly reduced and therefore there is a strong dependence on the temperature and groundwater level. It is established that the use of the adjustable level of groundwater is one of the methods of regulation of thermal regimen that allows creating optimal conditions for cultivation crops by way of integrated management of water-thermal regime in the root layer of soil. Conclusions. Studies have shown the possibility of achieving favorable temperature conditions of the soil at the period of sowing, of minimizing the harmful effects of late spring frosts, and of creating optimal conditions for the cultivation of agricultural crops during the growing season by way of integrated management of water-thermal regime in the root layer of soil.