The efficiency of waste hot water utilisation to improve the temperature conditions for growing plants

One of the rational ways of energy saving is to use the heat of wastewater from energy companies for open ground heating and cultivation crops. The most significant sources of heat are thermal and nuclear power plants that produce low-thermal waters of 28-35°C. Heating of the ground with the use of circulating warm water allows to increase temperature at all points of the soil profile. The maximum thermal effect from heating ground is observed at the depth of pipe heaters (7.3- 11.1°C). Ground heating allows to extend the growing season for crops by 3-4 weeks, which can expedite harvesting and thus maximise the harvest. In natural moisture conditions, ground heating does not lead to significant reduction of moisture reserves in the active layer throughout the growing period. There is a redistribution of moisture in a soil profile. It decreases in the zone of pipe heaters and redistributes toward the top. The formation of the nutrient regime changes, the content of mobile phosphorus and potassium, and nitrate nitrogen increases, whereas the content of ammonia nitrogen is reduced. Ground heating is a new special heat reclamation technique. It allows not only to control temperature of the agricultural crop environment, but also to dissipate heat in the ground, and promote the utilisation of waste heat and the stabilisation of the environment.