Mulches/mulching biodegradability

Shogren RL (2000) Biodegradable mulches from renewable resources. J Sustain Agric 16 33 17. doi 10.1300/J064v 16n04 05... 

On weed-free ground, a loose mulch, 4 in (10 cm) deep, will provide effective weed control. Any weeds that may appear are easily removed. An organic, biodegradable material is the preferred organic option as a bonus, this sort of mulch will attract beetles, centipedes, and other pest-eating creatures that enjoy the dark, moist conditions. 

Clockwise from top left) Biodegradable mulches An ornamental bark mulch, good around shrubs and at the base of hedges lawn clippings used as a mulch in the vegetable plot, here spread over layers of newspaper (see also overleaf)] one-year-old leaf mold well-rotted straw. 

A mulch membrane, weed barrier, or weed control fabric is simply a sheet of synthetic or biodegradable material that forms a physical and light-excluding barrier to weed growth. Membranes can be used to clear annual and perennial weeds from open ground and beds. They are also used to prevent weeds from growing on ground that has been cleared. 

Holes can be cut to allow planting through the membrane as appropriate. Membranes may be covered with a loose mulch, to hold them in place, extend their life span, and improve their appearance. A mulch membrane must be permeable, to allow air and water into the soil, unless it is only to be kept in place for a few months. However, to suppress the more vigorous perennial weeds (see also pp.80-81), the membrane may need to be in place for several years while there are several biodegradable choices of membrane material, a nonbiodegradable material is the more practical option in such situations. 

Mulch film PE o o 3 Paper Biodegradability depending on local climate is key issue... 

This application is very cost-sensitive because of the subsidy structure of the agricultural sector of the EU. The regulations for waste disposal of mulch film require either recycling or adequate treatment (e.g., incineration). If thin mulch films are concerned, the recovery of the film in the field is crop-dependent and difficult. Cleaning of the soil residues is cost-intensive. In this case, it can be more cost-effective to use biodegradable mulch film, which is adapted to the climate and the fruit application. 

For example, cucumber is harvested up to 25 times per growing season using heavy machinery. At the end of the season the mulch film is difficult to recover. For this application, the use of biodegradable mulch film is of interest. 

Since the most important property of mulch film is the appropriate biodegradability, extensive experiments in each region are indispensable. 

Agricultural mulching film is one of the typical applications for biodegradable plastics. Currently, Bionolle mulching film is commonly used in Japan, and is an important market for us. However, some farmers are anxious about the effects of repeated use of biodegradable plastic on the farm. We, as a manufacturer of Bionolle, need to accumulate knowledge on such usage in the farm. 

These kinds of products are normally used in mulch films, bags and packing. Other systems have been investigated. The combination starch/ polyester has been claimed to be fully biodegradable (Tokiwa et al., 1993). Others are partially biodegradable, like starch/polyethylene/poly-e-caprolactone blends (Corp, 2001) and their derivatives or combinations of starch and modified polyesters. 

As for other waste, the plan calls for glass to be crushed and used for road aggregate, metals to be sold or given away, and anything biodegradable to be composted for mulch. 

More recently, biodegradable plastics have been applied in other areas, including packaging and agriculmre (plant containers, mulch films, controlled release of chemical substances, etc.). After hydrolysis of PHAs, the follow-up products can be used as enantiomerically pure starting materials for chiral high price compounds [7-9]. 

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