What is spring and fall shed

Spring and fall shed, China in the fall of 1955 the introduction of polyvinyl chloride agricultural film, first used in Beijing to cover vegetables in small sheds, to obtain the effect of early maturity and increase production. The original greenhouse is a specialized equipment for vegetable production, with the development of the production of greenhouse application more and more widely. Currently, greenhouses have been used for potted flowers and cut flower cultivation; fruit tree production for the cultivation of grapes, strawberries, watermelons, melons, peaches and oranges, etc.; forestry production for forest nursery, ornamental tree cultivation, etc.; aquaculture used for silkworms, chickens, cows, pigs, fish and fish fry, etc..

The greenhouse is a light building, so the light transmission rate is the evaluation of the greenhouse light transmission performance of one of the most basic indicators. Transmittance refers to the greenhouse light into the amount of light and the percentage of outdoor light. Greenhouse light transmittance is affected by the greenhouse light transmittance covering material light transmittance performance and greenhouse skeleton shadow rate, and with the different solar radiation angle in different seasons, greenhouse light transmittance is also changing at any time. Greenhouse light transmittance becomes a direct influence on crop growth and the selection of planting crop varieties. In general, the continuous plastic greenhouse in 50% ~ 60%, glass greenhouse light transmission rate in 60% ~ 70%, solar greenhouse can reach more than 70%.