| 摘要 |
<p>Plastics film for covering cropping soil or frame structures, containing or destined to contain seeds, to cover seeded soil or soil destined to be seeded, is stretched beyond its yield point to achieve reduced thickness whereby the web quickly deteriorates to allow passage of germinated seedlings. Also claimed are (i) a film as above which is of non-ultraviolet resistant, photo or biologically degradable material, and the stretching reduces the thickness to 10 ~mm; (ii) a film as above which is a dual ply film which may have air trapped between the plies; and (iii) a film as above which is subjected to further localised stretching in a pattern or lines to encourage crop egress in the pattern or along the lines.</p> |
