18 Pages

Photo-deqradable Plastics in Agriculture

WithDan Gilead

Plastic baling twine and plastic irrigation tubing accumulate in the fields and by the wayside and are causing an eyesore and a nuisance. The greatest problem is caused by agricultural films used for mulching. These films used by themselves or in conjunction with plastic tunnels have created an entirely new agrotechnical method known by the name of Plasticulture. Simple calculation of the quantities involved will show that in several hundred years of continuous use of photo-degradable films not more than one part per million will be added, ignoring the fact that some quantity will be removed by the crops. It is obvious that degradability must be closely controlled as the films have to perform their agrotechnical tasks before becoming redundant. Under the conditions films have to have great mechanical strength, especially tear resistance and impact strength. The amount of irradiation present at a given location will depend on latitude, season and altitude. Storability will not be reduced but may well be better than that of regular films.