塑料大棚生产现状与展望

来源 :上海蔬菜 | 被引量 : 0次 | 上传用户:heartless850
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
一、棚型结构我市暖和多雨,大棚主要用于冬、春、秋三季,单只大棚面积0.25亩左右。结构有三种,以竹木结构最多,钢管大棚次之,钢筋棚最少。(1)装配式镀锌钢管棚这种棚架强度高,寿命长,装卸容易,中间无支架,透光性好,防锈盖膜方便。规格有6米宽和4.5米宽两种,一般20-30米长。但一次性投资大,每亩成本万元以上。 First, shed structure Warm and rainy city, the greenhouse is mainly used for winter, spring and autumn quarters, a single shed area of ​​about 0.25 acres. There are three types of structures, with the most bamboo structure, followed by steel pipe shed, steel shed at least. (1) assembled galvanized steel shed This scaffolding high strength, long life, easy loading and unloading, the middle stent, light transmission, rust-proof membrane convenient. Specifications are 6 meters wide and 4.5 meters wide two, usually 20-30 meters long. However, a one-time investment, the cost per million yuan per mu.
其他文献
题目作者   期 (页 )气象学 环境科学适用于多指标的水环境质量评价的普适指数公式李祚泳 邓新民  1 (1 0 )………………………………………超低温结构在长期预测中的
The principles of Gradient operator, Laplacian operator, LOG operator and Sobel operator are discussed. Certain features of breast can be extracted in different
我队轻型山地工人,为了提高深槽的掘进效率,根据槽深量大的特点,创造了半自动化出碴装置,在深槽探使用此种设备,一人既可连续地进行掘土出碴工作,同时可减轻体力劳动和提高效率50%以