Hydrothermic regime management of the irrigated field while growing early potatoes in the arid zone

The problem of obtaining consistently high yields of early potatoes while minimizing the cost per unit of production is very serious. Improving the technology of growing potatoes in the dry steppe zone with the integrated irrigation and fermentation systems is aimed not only at meeting the needs of the population in these products in the region, but also at reducing the demand for the purchase of potatoes abroad.

The dynamics of the main factors of plant life associated with the state of the environment, and the needs of plants at different stages of development may differ significantly from each other, which leads to a decrease in the intensity of the production process and yield. Regulation of the hydrothermal regime of crop during the critical periods of plant vegetation can be a useful agrotechnical method in managing the water regime and productivity of potatoes in the conditions of the dry steppe zone.

The use of digital technology for regulating the water-thermal regime of irrigated crops with using simulation models is caused not only by the specifics of the problem being solved, but also by the requirements for updating irrigation and drainage systems based on the modern technical advances and fundamental knowledge in order to implement highly efficient and environmentally friendly farming on reclaimed land.

Results of multifactor experiments on potatoes cultivation under drip irrigation and finely divided sprinkling in the conditions of the Volgograd region did not allow us to identify optimal technological parameters with apply of statistical methods. In addition to the small number of field experiments over a number of years, the high variation of weather conditions was the dominant factor, that is leading the shifts in vegetative growth period duration and the most significant stages of potato growing.

The prospect to solve this problem is recognized in application of a dynamic model for the potato crop growing that considers the ability to control soil moisture in the root zone and temperature regime of the vegetation cover and simulate them depending on the emerging weather conditions and the actual state of the plants. Using the J. Richie algorithm to determine evaporation and transpiration, it is easy to reconcile the design scheme with soil moisture distribution under drip irrigation, and also consider the agrocenosis water balance with periodic fine dispersion water sprinkling when the set air temperature is exceeded in the hottest hours of the day. Preliminary numerical experiments, based on the retrospective data of earlier field experiments, indicate sufficient flexibility of the model in terms of the formed water-temperature regime simulation and its influence on potato growth processes.

In 2019, the technology of growing early potatoes was tested using a dynamic model in the Ryazan region for the temperate climate of the forest-steppe area. The model showed adequate results of its application to control the hydrothermal regime in irrigation by sprinkling.

The research is carried out under the Grant of the RFBR 19-416-343004 р_мол_а with the support of the Committee for Economic Policy and Development of the Volgograd Region.