Plastic mulch

As mulch films or films horticulture plastic films are referred to in the agriculture and horticulture, which serve to cover the ground of beds or arable land. For the crops to be grown, the film is perforated at the point of sowing or planting. Mulch films are used primarily in vegetable and strawberry production.

Effect

The cover leads to a warming of the earth's surface located under the foil of about 2 ° relative to the environment, so that the plants get better growth conditions in cool temperatures - in the summer but also to excessive heating of the top soil layer is possible. Because of the homogeneous conditions under the film, the growth pattern of the crop is more uniform. The soil beneath the plastic mulch remains loose and dries less quickly. The tilth and soil fertility is encouraged. In addition suppressed the use of black film weed growth on the covered surfaces and can thus reduce the need for the application of herbicides. The propagation of certain plant diseases (for example, gray mold ) and the leaching of nutrients can be reduced. The end result raises an increase in yield and earlier maturity of the fruit. Further, the outer quality of the fruit is enhanced, since the mulch film prevents contamination of the crop. Disadvantage of the use of plastic mulch may be that the aerial parts of the crops can be damaged more by night frosts due to the reduction of heat radiation during the night through the soil cover.

Materials

Mulch films are made usually from a polyethylene film, making them partially for years to remain lying for weed suppression under gravel paths or mulch beds without rotting. The film material is usually dyed black, but there are also white (so-called milk films) or transparencies used.

Alternatively, mulch films consist of biodegradable bioplastics, such as from renewable resources. The main advantage of these films is their compostability. The films rot usually after about three months and save so especially in large companies collecting the slides after the harvest; the rotting remains can be easily plowed under or disposed of in the compost. In addition to biodegradable films made from starch polymers and films based on lactic acid ( polylactide polymers or PLA) have been available since 2007, which allow a prolonged use because of a slower biodegradation.

The tensile strength of biodegradable mulch films is higher than that of comparable polyethylene mulch film thickness because of their elasticity, so is through the use of less material strength a material saving of around 50 % is possible.

Because of its significantly higher price, however, the use of mulch films based on renewable resources is not yet cost effective only in certain applications and their market share correspondingly small. In a direct cost comparison 2006, about double the price was calculated as for a comparable polyethylene film for the use of a biodegradable mulch film. In an economic analysis, however, the costs for the collection, cleaning and disposal of polyethylene plastic mulch must be included.

Use

In Germany mulch films were used in 2008 to 3,935 hectares. In 2010, market sales in Germany of 18 million euros and for 2020 of EUR 100 million is forecast for mulch films from renewable resources. In order to demonstrate large areas in a short time with film, film laying machines are used mostly. These lay in a single operation from the foil and cover the edges of the foil to attach to ground.