Modeling the process of management of water-salt and food regime of salt soils of marginal land using waste water

Following the development and further improvement of the ecosystem approach to the development of saline marginal lands, a theoretical justification has been prepared for the conceptual model of the technology for the management of the salinity and nutritional regime of marginal lands, where the development of such land takes place in three symmetrical and parallelsequential actions in time at annual intervals on the basis of using biologinization of agriculture, programming productivity of agricultural crops with desalinization of the saline soil to a certain acceptable level subject to leaching limit and chemical reclamation, taking into account the environmental management requirements and classification of the saline soil and salt tolerance of agricultural crops. In addition, the distinctive peculiarities of the proposed technology are the possibility to implement the entire complex of environment-forming functions of the natural system, including the assessment of energy resources of the soil and vegetation cover (various agro-ecological categories), productivity of agricultural land using the reference yield methods, water consumption deficit of agricultural land and leaching limits, ensuring the gradual achievement of the safe level of salinity, using the biological characteristics of salt-tolerant crops (halophytes) and chemical reclamation, based on application of gypsum to the topsoil, owing to a balanced supply of mineral fertilizers, and based on their rationing, taking into account planning the yield of cultivated crops. To illustrate the capability of the presented models, a two-year field experiment was conducted on saline lands using wastewater in the Kyzylorda region of the Republic of Kazakhstan and the results showed that supplementing the information with data from actual measurement results will provide even greater adaptability of the model. Based on the experimental research conducted to explore the possibility of managing the water-salt and nutrient regimes of soils in marginal lands using wastewater and salt-tolerant crops, and developed through mathematical models of soil water, salt, and nutrient dynamics along with a control technology algorithm for these natural-technogenic processes, it was demonstrated that the theoretical justification and the proposed conceptual model of the software and hardware system for managing the soil water-salt regime under wastewater irrigation comply with environmental protection requirements and align with the ecological, economic, and social aspects of the sustainability triad. The materials and methods of this manuscript, except for the experimental part of the study were presented as a preprint in Research Square (Mustafayev et al., 2024).