The Optimization Of Environmental Parameters And Equipment In Greenhouse For Seedling Production In South Of Guangxi

The purpose of this essay is to solve the problem of high costs and the impropriety of greenhouse building and environment regulating on seedling production in south area of Guangxi province.Using the general rotary combination's regressive design, the relationship between the photosynthetic rate of eucalyptus seedlings (D-2) and environmental factors was studied. The regression equation between temperature (X1), light intensity (X2), carbon dioxide concentration (X3) and photosynthesis was achieved by using SAS software for data processing.The heat and cold preservation capability of all kinds of greenhouse combination in southern area of Guangxi province has been measured for about one year. The result indicated that the indoor temperature of the greenhouse was 0.5～4.0℃higher than outdoor temperature when doors and windows were closed. If a piece of airproof plastic membrane was added to the top and four sides of the greenhouse, the difference in temperature changed into 3.1～6.6℃with a lower transmittance and lighter intensity. Using the fan-pad add cladding cooling device, the indoor temperature could be 2.5～6℃lower than outdoors. If skylight and side windows were used with spray system, the temperature inside will be 1～3.5℃lower than outside. Besides, the transpiration of plants could make contribution to the temperature difference to 4.5℃.According to the optimization theory, the photosynthesis function model was optimized, showing that the maximum function value(Ymax) was 36.89μmol.CO₂(/m²S). The corresponding value of three factors was as follows: the temperature was 27.1℃, PAR 487.93μmolm^-2s^-1 and carbon dioxide 700.ppm. At the same time, the reasonable value range of temperature and PAR of some typical climate in southern area of Guangxi province was optimized and confined in view of the difference among four seasons. Moreover, a new concept of consistence photosynthesis of seedling production was mentioned and the chart of environmental factors of consistent photosynthetic rate was drew which provide the convenience for artificial selection of environmental factor level. Furthermore, the photosynthesis function of special climate was also optimized considering the climate characters and the regulation capability of this area. Finally, the outdoor light intensity deciding the opening of cladding net was confirmed.According to the investment charge, number of year for using, regulation effect of environmental factors and controlling costs, the concept of largest photosynthesis of unit costs on seedling production was mentioned. The photosynthesis of unit costs on six typical kinds of greenhouses in the area were calculated and compared. The optimum combination of greenhouse equipment for eucalyptus seedling production showed that the greenhouse with highest quality-price ratio was the plastic greenhouse...