To define the strategy for the reclamation measures management, as well as to evaluate their effectiveness, the authors proposed to use simulation methods of the soil-plant-atmosphere system based on accumulated domestic and foreign experience and experimental material obtained from early potato plantings in the Volgograd region. The main factor affecting the yield of agrocoenosis is the moisture availability to the plant in the soil layer occupied by roots, and therefore, special attention should be paid to evaporation and transpiration modeling, and the movement of moisture in the soil profile during the irrigation (drip and sprinkling) and precipitation. The article describes the algorithm for calculating water exchange. The mathematical model is implemented by using standard Microsoft Excel software, which makes it accessible and simple enough for the user.

The statistical analysis of the irrigation water volume and air temperatures sum influence on the average rice productivity in the irrigation systems of the Lower Kuban is presented in the article. The analysis was performed by using quadratic and power regression equations; the each factor contribution to the productivity value was estimated by the statistical significance of the regression, correlation and determination coefficients. The rice culture sensitivity to the irrigation regime - to the water volume supplied to irrigation systems, and to the temperature regime according to the vegetation months, was analyzed. It was found that only during two months of the growing season - July and September, high temperatures and irrigation water scarcity lack provide a synergistic effect in relation to the high yield formation.

<p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p>

Анализ водопользования рисосеющих агрокомплексов в зоне Нижней Кубани свидетельствует о напряженной водохозяйственной ситуации, обостряющейся в маловодные годы. Возникающие дефициты водообеспечения наносят существенный ущерб всем водопользователям и особенно отраслям сельского хозяйства. Предлагаемые авторами подходы совершенствования водообеспечения и водопользования оросительных систем базируются на разработке интегрированной системы управления распределением водных ресурсов и продуктивностью агромелиоративного комплекса. Новая технологии управления строится на двух взаимосвязанных оптимизационных задачах, решаемых в одном пространственном и временном формате: с помощью динамической гидравлической модели формируются и изучаются оптимальные варианты подачи поливной воды от водоисточников до орошаемого поля, а модели продуктивности отражают влияние параметров водоподачи на урожайность культур. Гидродинамическое моделирование позволяет формировать режимы работы водохранилищ и гидроузлов таким образом, чтобы с одной стороны обеспечить командные высоты на водозаборах, а с другой, удовлетворить конфликтующие интересы водопользователей, в том числе сельхозпроизводителей. Выработка приемлемого управленческого решения реализуется методами многокритериального анализа и теории компромиссов с ориентацией на прогноз недобора урожая в зависимости от варианта вододеления.Analysis of water of rice-growing agricultural complexes use in the Lower Kuban region indicates a tense water management situation that worsens in low-water years. Occurring water supply deficits cause significant damage to all water users and especially to agricultural sectors. The approaches proposed by the authors to improve water supply and water use of irrigation systems are based on the integrated management system for the water resources distribution and productivity of the agro-reclamation complex development. The new management technology is based on two interrelated optimization problems that are solved in the same spatial and temporal format: optimal options for irrigation water supply from water sources to an irrigated field are formed and studied using a dynamic hydraulic model, and productivity models reflect the influence of water supply parameters on crop yields. Hydrodynamic modeling allows you to form reservoirs operating and hydroelectric facilities modes in such a way that, on the one hand, provide command heights at water intakes, and on the other, meet the conflicting interests of water users, including agricultural producers. The development of an acceptable management decision is realized by using the methods of multi-criteria analysis and the theory of trade-offs with a focus on the forecast of crop deficit depending on the water allocation option.

The object of research is irrigation systems that are hydraulically connected to a large specialized agricultural complex for rice production, located in the lower part of the Kuban River basin and experiencing an acute shortage of water resources. In the last decade, rice irrigation area decreased by 50%. Calculation technology is proposed for water resources management of the Lower Kuban basin basing on integrated use of six models developed in Russia: hydrological and meteorological forecasts; simulation models of yield formation to calculate crops water demand; water balance models to develop water use schedules for irrigation systems; hydrodynamic models to calculate water use scenarios; optimization models to choose a trade-off Pareto management options; and statistical models to calculate yield losses depending on water resources deficit. This technology allows adopting optimal trade-off solutions online with the Lower Kuban water resources management in interests of agriculture.