Study On Light And Temperature Environment Of Northwest Energy-Saving Sun-light Greenhouse

Four different structures of sun-light greenhouses were studied in Yangling Hi-Tech Agricultural Demonstration Zone of Shaanxi province. Light intensity, air temperature, soil temperature and atmosphere humidity inside and outside of greenhouse were observed in sequence. Light and temperature character, tomato growth, yield, economy benefit and produce cost of four different structure of sun-light greenhouses were analyzed. The main results were as follows:The transmission ratio of Greenhouse 1 could be 73.50%, 16.20% higher than Greenhouse 4. There was small difference between Greenhouse 2 and Greenhouse 3,they were 66.30%, 68.10%. Greenhouse 3 (semi-underground greenhouse)was the best one in heat preservation ,The ratio of heat preservation of Greenhouse 3 is 0.94,In sunny day, the surplus of quantity of heat is 15. 81 千 KJ/m2, the average lowest temperature is above 10℃. the next was Greenhouse 1, The ratio of heat preservation is 0.88, the surplus of quantity of heat is 13. 01 千 KJ/m2, the average lowest temperature is above 9℃. In sunny day, the average higher temperature in Greenhouse 1 and Greenhouse 3 was increased by 6-8℃ than Greenhouse 4. The structure parameter of Greenhouse 1 and Greenhouse 3 is in reason . They were suitable for the western area climate.Comprehensive evaluation, Greenhouse 1 was the most valuable in utility. The yield of winter-spring tomato in Greenhouse 1 could be reach 5125-7932.8/666.7m2,the benefitcould be 25000RMB/666.7m ,the ratio of investment and output would be 1.:3.2 ,and the utilization of the land was 0.80. It was fit for the region of annual average temperature of 10-15℃, the extremely lowest temperature is -20℃.Enhance the thickness of wall and covering material could enlarge the expansive district. The yield of winter-spring tomato in Greenhouse 3 could reach 5328.6- 8197.8Kg/666.7m2, the benefit could be also25000RMB/666.7m2 , the ratio of investment and output would be 1: 2.67. The characteristics of light and warm were also perfect. But the utilization of land was too low, just 0.65,and it was easily suffered surface waterlog, It was adapt to extend in high latitude or weather colder or reacher land area. Greenhouse 4 was no longer adaptable for extending.