Temperature And Light Characteristics Of Assembly Sunlight Greenhouse And Its Effect On Tomato Production

The northern winter is cold and long,and the outdoor temperature is too low,which causes the indoor temperature to drop and affects the growth of vegetable crops.To keep the crops from freezing to death,consequently,the greenhouse need to be heated with cons uming energy,which means that the cost of investment will increase that seriously restricts the large-scale promotion of solar greenhouse.At present,there are poorly reports about the research on the internal environment change rule of the built-in heat preservation solar greenhouse,new material structure and enclosure structure in Heilongjiang province.Although the lack of solar greenhouse thermal insulation has become a major problem restricting the promotion of energy-saving solar greenhouse in the north of China,but the intention for saving greenhouse production costs in winter has never changed.This experiment combined the research points of solar greenhouse thermal insulation,based on the structural characteristics of internal thermal insulatio n solar greenhouse,considering from three different management perspectives of cotton quilt uncovered and covered methods,inner layer transparent plastic film uncovered and covered methods,and ventilation methods,meanwhile verified by vegetable crop growth as an auxiliary means.The objective is to determine the optimal methods of cotton quilt uncovered and covered,inner layer transparent plastic film uncovered and covered,and ventilation of the solar greenhouse,which provides certain theoretical basis for clearing the greenhouse performance and optimizing the greenhouse management of this type of assembled energy-saving solar greenhouse.Through the experiment,the following results are obtained:(1)The performance of the assembled energy-saving solar greenhouse is superior.Under low temperature conditions of-26.9? outdoors in winter,the indoor temperature can be maintained above 7.2?.The light intensity is decreasing from south to north.In sunny days,the ground temperature increases successively from south to north;In cloudy day,the central air temperature is the highest,followed by the north,and lowest in the south.In the direction of east to west and south to north,the air temperature in the central part is the highest,but the air temperature difference is smaller,which the distribution is relatively uniform,and the plant growth is relatively neat.(2)The best way with cotton quilt uncovering and covering for winter sunlight greenhouse that was appropriate uncovering early and covering lately was that the time of uncovering and covering cotton quilt was 8:30 and 15:00.Cotton quilt are uncovered later than sunrise and covered earlier than sunset in winter,within a certain time of uncovering and covering,the treatment of MB-1 with cotton quilt uncovering at 8:30 and covering at 15:30 was obviously better than the treatment of MB-3 that the time of cotton quilt uncovering and covering were 9:30 and 14:30,and was not obviously different compared with the treatment of MB-2 with cotton quilt uncovering at 8:45and covering at 14:45.However,at different treatment times,the growth of tomato at MB-1 treatment was better than MB-2 treatment.Generally speaking,the method with otton quilt uncovering at 8:30 and covering at 15:30 was beneficial to environmental regulat ions and the growth of tomato in winter greenhouse.(3)The best way with inner layer transparent plastic film uncovered and covered for winter sunlight greenhouse that was appropriate uncovering lately and covering early was that the time of uncovering and covering inner layer transparent plastic film was 75 minutes after uncovering the quilt and 75 minutes before covering the quilt.The inner layer transparent plastic film of the greenhouse must be managed according to the uncovering and covering methods o f the cotton quilt.On winter mornings,a layer of ice crystals will always be attached to the surface of the outer layer transparent plastic film,after the cotton quilt is uncovered,the ice crystals will not melt for a period of time,so during this period of time,do not uncovering the inner layer transparent plastic film early.In the afternoon,the solar radiation will be weakened,close the inner layer transparent plastic film in advance to keep warm.(4)The best way of ventilation for winter sunlight greenhouse was conducting ventilation for 30 minutes when the indoor temperature reaches 30?.When ventilation is carried out,the ventilation time is too long,and it is easy to cause the indoor temperature to be lower than the temperature suitable for the growth of the crop.Properly reducing the duration of ventilation can improve the air temperature,ground temperature and other environment of the greenhouse,which has a good effect on the chlorophyll content,root activity and tomato yield of crops.