Research On Ecological Dynamics In Sunlight Greenhouse Of Northern Areas

Energy-saving solar greenhouse is the main force of facilities-agricultureproduction in China. And it plays an important role in off-season vegetable productionin northern China. It is the most important issue that how to minimize energyconsumption and increase efficiency for greenhouse production.This paper summarized and absorbed domestic and foreign research results.According to climate characteristics and ecological characteristics of crops ingreenhouse in northern region, microclimate environmental issues in sunlightgreenhouse have been analyzed in passive situation, and a reasonable correlationbetween environmental parameters and influence factors in sunlight greenhouse hasbeen established by using combination method of Computational Mathematics andStatistics Mathematics about agricultural ecology and dynamics. The solar radiationdynamics prediction model, air temperature and air humidity prediction model havebeen build which is suitable for northern region. These models can predict the trendsof daily environment parameters such as solar radiation fluxes, air temperature and airhumidity in greenhouse with time changing. The relationship between greenhouseenergy balance and environmental factors was gotten. A comprehensive study of thefactors' impact on greenhouse thermal environment was carried out. The reasons forgreenhouse heat loss were analyzed. Thereby recommendations for greenhouse designand energy saving production in winter will be provided.The Environmental factors such as inside and outside solar radiation, inside andoutside air temperature and humidity, inside and outside wall surface temperature andheat fluxes, inner surface temperature and heat flux of the back slope, and soiltemperature at different depths and heat fluxes were observed continuously. Thesimulated test on the models by a large number of experimental data was carried out.The results show that the accuracy of simulation results and trends are in goodagreement. The prediction accuracy of model is high. The coefficient of determinationis more than0.85, and the average value of relative error is less than15%. The lightand temperature performance characteristics of greenhouse were analyzed by usingobservational data.By estimating effective accumulated temperature of greenhouse at different times,the model of the effective accumulated temperature has been built in sunlightgreenhouse. This model can effectively predict the growth period of plant, and willplay an important guiding role in reasonable arrangements for vegetable plantvarieties and planting times in solar greenhouse.