In article there is a speech about use of a film hothouse in vegetable growing. Existing types of films are listed. The characteristic and range of application of a film hothouse is provided.
UDC 635
Many vegetable growers dependence of quality of films on additives etc. interests existing types of films, their properties.
The main enemy of polyethylene films – ultra-violet radiation destroying them. To increase durability of a film, into a material enter svetostabiliziruyushchy and anti-oxidizing additives that increases term of its operation till 2-3 season. Therefore for hothouses it is necessary to use only the stabilized films. The Antifogovy additive allows to avoid condensation of drops of moisture which, flowing down on a film, getting on a plant can cause burns.
The film with svetosberegayushchy properties comprises additives – phosphors, reformative an ultra-violet part of a range of sunlight harmful to plants in visible, the most useful to photosynthesis. It allows to keep night temperature in a hothouse on 5-8 degrees above, than under a usual film. Under such film terms of vegetation are reduced by 1,5-2 weeks and productivity for 25-50 % raises.
There are films single-layered and multilayered. The purpose of manufacturing of a multilayered film – decrease in its cost. For example, if antifog to enter into all mass of a film, its price increases for 25 %. Therefore to reduce the price of a film, some components add only in one of layers.
The coloring of a film used for hothouses, doesn’t play a special role. The producer chooses color on the taste. Amount of the dye entering into composition of polyethylene, so slightly that in expanded form the film is colourless. All necessary data on a film are specified on labels.
However, there is also a colored film which isn’t applied to a covering of hothouses, and is used, for example, for shelter of beds.
Recently the film with bilateral coloring (black-and-white), used in hothouses is issued. It stack the black party to soil that interferes with development of weeds. And top, white, the party plays a role of the reflecting screen. At dye with shine it allows to save 15 % of the electric power during the autumn and winter period. At usual coloring the effect appears twice below. The black-and-white film is simply necessary for large-scale hothouse enterprises, where bycicles of an expense for the electric power.
(On Ovoshchevodstvo magazine materials).