Study On Structural Parameters And Melon Planting Strategy In East-west Ridge For Chinese Solar Greenhouse

As a typical energy-saving horticultural facility,Chinese solar greenhouses make full use of solar energy to achieve the long-term supply of vegetables in cold regions of China.However,with the development of greenhouse industry,there are still low solar energy utilization and low mechanization level.To solve the above problems,many scholars used the simulation model to optimize the greenhouse structure and proposed the east-west ridge cultivation mode.However,in the process of simulation and optimization,the empty greenhouses were taken as the research object,ignoring the existence of crops.Moreover,there is also uneven light distribution in east-west ridge cultivation.Based on the above background,this paper takes the light interception of crops as the evaluation index to systematically explore the optimal lighting structure parameters of the Chinese solar greenhouse.On this basis,the feasibility of replacing traditional north-south ridge planting with east-west ridge planting and the corresponding plant configuration were further determined.Therefore,this paper uses the traditional experiment combined with virtual simulation research method,and taking the most widely used the second generation solar greenhouse and large planting area of light crop melon as the research prototype.Through the actual measurement of the geometric structure and optical physical parameters of melon crops in the experimental greenhouse,combined with the virtual sky model to realize the reconstruction of the three-dimensional virtual solar greenhouse and the construction of the optical simulation model.Further,through the quantitative study of orientation,ridge height,horizontal projection of rear roof,ridge direction and other parameters of Chinese solar greenhouse,the following conclusions are drawn:(1)By comparing the measured solar radiation intensity data of wall,ground and crop canopy inside experimental solar greenhouse during winter solstice with the corresponding light simulation data,it is concluded that the minimum value of fitting degree(R~2)for light interception data is 0.9472,which indicates that the model accuracy is high.(2)For the the second generation solar greenhouse in Shenyang area,taking the maximum light interception of the maintenance structures of solar greenhouse as the evaluation index,the greenhouse orientation should be 8-10°S-W.For the maximum light interception of crops,the greenhouse orientation should be 4-6°S-W.For the most common 9 m span,2.9 m wall height of the second generation solar greenhouse,the suitable ridge height is 4.9 m,the horizontal projection of the rear roof is 1.6 m.(3)Under the same cultivation density,for the second generation solar greenhouse,based on the light distribution law of melon plant population,the suitable cultivation mode for east-west ridge can replace the traditional cultivation mode of north-south ridge.The suitable plant configuration is east-west ridge,ridge spacing 120 cm,row spacing 40 cm,plant spacing 38cm.In summary,this model can simulate and analyze the crop light environment in Chinese solar greenhouse with high precision.Furthermore,the model can be used to optimize the configuration parameters of greenhouse,such as structure parameters and plant spacing,so as to provide theoretical guidance and scientific basis for the reconstruction of solar greenhouse and crop planting strategy.