Studying On Greenhouse Irrigation Technology With Underground Diving During Winter In The Low Temperature Region

In view of greenhouse at high altitude area in low temperature zone in Northern China using surface river water to irrigate in wintering period, this paper tracks and monitors a series of temperatures on site, including the temperature of surface river water, diving well water, impounding reservoir, heating pool in greenhouse as well as the local temperature. Then, the paper analyzes the quantitative relation among the temperature of wintering period, temperature of surface river water and diving well water, the temperature of diving well water and impounding reservoir, the temperature of impounding reservoir and heating pool. The results are as follows:1. The local temperature synchronizes with the temperature of surface river water. After the ice cover forms on the surface layer of surface river water, its temperature tends to be relatively stable. When surface river water flows through the gravel layer into diving well, the temperature of diving well water also keeps relatively stable in wintering period due to the heat conduction of geothermy. The temperature of seepage field is the main factor that influences the temperature of diving well water. The local temperature has little influence on the temperature of diving well water. The lid of diving well and deepening the diving well depth can effectively increase the heat supply and reduce the heat loss, which raises the temperature of diving well water.2. There exists a certain correlation between the water temperature change of impounding reservoir and diving well water. In wintering period, the temperature of impounding reservoir is relatively stable, because the ground conducts the heat to water during the water delivery. But in January when the local temperature is lowest, the water temperature is higher than the ground temperature, a part of water temperature will be conducted to the ground, which reduces the temperature of impounding reservoir. Thus, deepening the buried depth of water pipe can help ground conduct heat to the water and effectively reduce the heat loss during the water delivery. Meanwhile, heat preservation should be given to the top and external wall of impounding reservoir. Thermal insulation material can be used to avoid the outside cold air, which has certain heat preservation effect on impounding reservoir.3. There exists a good linear correlation between the water temperature change of heating pool’s water inlet and impounding reservoir. The temperature of impounding reservoir directly influences the water temperature of heating pool’s water inlet. The water temperature can be raised9-10degrees Celsius after entering the heating pool, so the temperature of irrigation water can be significantly raised. At the same time, other technologies can be used to effectively raise the temperature of irrigation water, such as the use of heating technology in heating pool, heating technology in channel, the control of irrigation water, water-saving irrigation technology, etc..The research results show various factors which influence the temperature of irrigation water, and methods of raising the temperature of irrigation water are also proposed. All of these can provide a certain technical support for greenhouse in low temperature zone in wintering period.