| Energy saving solar greenhouse is a kind of greenhouse structure type with Chinese characteristics.The development of greenhouse facilities has made great contribution to the sustainable development of agriculture in our country,It is the future development direction of low carbon greenhouse under the trend of international environmental protection.In recent years,many problems restricting the development of greenhouse are becoming more and more serious.Especially,the shortage of greenhouse thermal insulation has become the bottleneck problem of greenhouse vegetable production in winter and spring.This experiment combining with the key points of the research on the heat preservation of greenhouse,start from the follow angles First,selected polystyrene board(EPS)and polystyrene extruded board(XPS)as the thermal insulation material,explored the effect of different position of heat insulating panel and different materials on soil temperature in greenhouse.Second,explored the practical effect of different external thermal insulation materials in the wall insulation of solar greenhouse,under the same thermal insulation resistance,third,designed the non non circulating water curtain system,explored the effect of temperature increase in different space heat capacity ratio(volume of heat storage water: greenhouse space volume).The main results showed that:(1)The heat insulation panel of foundation,both external and built-in,were significantly better than the contrast,and the insulation position significantly affects the greenhouse temperature.heat insulation layer built-in insulation is better than external.In particular,the built-in processing level average temperature was significantly higher than that of the external temperature,average increased0.5℃,and significantly increased the better uniformity,the average temperature in vertical direction in the range of 5cm-25 cm average increased 0.6℃,and the lowest temperature also increased significantly.(2)In the greenhouse with built-in insulationt,the chlorophyll content of tomato planting period,the root activity was significantly higher than external,tomato yield is increased by 13.4%.and the plant height,stem diameter,different period of flowering in fruit is better than external.(3)Under the same thermal resistance value,the XPS thermal insulation external,effect of the foundation is better than that of the EPS,which is shown in the following aspects: the level average temperature increased 0.3 ℃ compared with EPS thermal insulation external,the vertical temperature performance of the 2~20cm is significantly better than that of the latter,the average daily temperatureof the horizontal direction is higher than that of the EPS.(4)Tomato in the greenhouse with XPS external,the plant height,stem diameter and root activity of Tomato in different periods were better than EPS,and the yield was 4.6% higher than that of EPS;(5)All the treatments with different external heat preservation materials were better than the contrast,and the polyurethane performed best,second is XPS outside,and the worst performance is phenolic ester.Specific performance in:the soil,air temperature,and the temperature difference between day and night are obviously higher than the contrast and other treatments,wall heat accumulation and wall temperature also increased significantly.(6)According to the analysis of growth related index of tomato in greenhouse with different external heat preseavation,tomato in polyurethane treatment,chlorophyll content and root activity at different period,stem diameter,yield than other treatments significantly increased the plant height,stem diameter,flowering and fruit setting rate is also better than the other treatments,the overall performance optimal.(7)The comparison of temperature increasing effect between the non circulating water curtain system,space capacity 1:113 is best,and next is 1:148,which had no significant difference,but significantly better than the 1:212.the treatment of 1:113 solar energy utilization rate is the highest,the air,soil temperature are the best,and the difference analysis shows that to achieve the significant warming effect of temperature.,the minimum space heat ratio should not be less than 1:148.(8)With non circulating water curtain system’s space heat ratio is 1:113.chlorophyll content and root activity of tomato at later period increased significantly,significantly raised the level of yield,and the same period of tomato plant height,stem diameter and other indicators are better than the other treatments and contrast. |
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