论文部分内容阅读
七十年代以来,北京郊区蔬莱保护地生产有了较大的发展。塑料大棚、玻璃温室生产的新鲜莱蔬在解决四、八、九月及冬季鲜莱淡季供应上起着越来越大的作用。随着城市人民生活水平的不断提高对鲜莱的数量和质量的要求也越来越高。因此在发展塑料大棚和北京改良式玻璃温室的生产基础上,从一九七五至一九七九年北京市先后自建和从日本引进了蔬莱大型温室成套设备。每幢生产温室面积都在5000米~2以上,大的在2万米~2以上。达样大面积的温室通风换气能否及时、适宜,就成为影响温室蔬莱生产的关踺问题之一。
Since the 1970s, there has been a great development in the production of protected vegetables in the suburbs of Beijing. Plastic greenhouses, glasshouses produce fresh Lai vegetables in the fourth, eight, September and winter Xianlai seasonal supply plays an increasingly important role. With the continuous improvement of living standards of urban people, the quantity and quality of Xianlai are also getting higher and higher. Therefore, on the basis of developing the plastic greenhouse and the production of modified glass greenhouse in Beijing, from1975to1979, Beijing has successively built and built a complete set of large-scale greenhouse equipment for vegetables from Japan. Each production of greenhouse area in 5000 meters ~ 2 above, large in 20000 ~ 2 above. To a large area of greenhouse ventilation can timely and appropriate, it has become one of the problems that affect the production of greenhouse vegetables Lai.