Environmental aspects of subsurface irrigation and development of a mathematical model of a double-circuit solar heating system

Abstract

This article discusses the method of subsurface irrigation of agricultural crops. A technological system for subsoil irrigation has been developed using an industrial base for the production of perforated polyethylene pipes of small diameter. In the first moments of water supply for irrigation, when the soil has low initial moisture, the flow through the perforations is maximum. This leads to an intensive increase in the humidification circuit. As the water flow stabilizes, the increase in the size of the circuit in the horizontal and vertical directions practically stops, and further deformation of the humidification circuit occurs mainly due to gravitational forces. When the hydrostatic head at the entrance to the subsurface irrigation system increases above 70 cm, the spread of moisture in the soil in the horizontal and vertical directions increases slightly, but this can lead to the danger of soil destruction and water wedging out on the soil surface. A mathematical model of thermohydraulic processes in a thermosiphon system designed for watering the cultivation layer in solar greenhouses during the cold season according to the subsoil irrigation scheme has been developed. The dynamics equations of all functional blocks were taken into account in accordance with the accepted assumptions.