Question of the Week
Answer: Plastic mulch is used in vegetable production for a number of reasons, including soil warming, reduced evaporation, increased yield and earliness, reduced nutrient leaching, and improved nutrient uptake. Of course, there are downsides to the using plastic as mulch, too. These include cost of the material and greater labor and equipment expense to apply and remove the mulch, as well as disposal fees that can be significant.
The first consideration on alternatives is what the primary objective is for using the black plastic mulch. Is it weed control? Increased soil temperature? Moisture control? Most growers in the Northeast use plastic mulch to increase soil temperature and weed control is a secondary bonus. A study, listed in the Resources below, was conducted by Washington State University on Alternatives to Plastic Mulch. In their trials, the Envirocare films, which are a thermal/ photo degradable plastic comosed of polyethelene + TDPA) were comparable to black plastic in durability, crop yield, soil temperature and affordability. While the Envirocare films are similar to black plastic, they degrade much faster with sunlight and air. This is not a product that you would want to just leave in the field; however, you could put it on a corner of your farm and with time it will degrade.
Kraft Brown paper and another thick paper mulch from New Zealand called EcoMulch have shown effectiveness in preventing weeds, but do not warm the soil surface as much as a plastic or other poly-based mulches.
Consistently in field trials black plastic produces better and earlier yields than the alternative mulch counterparts. That is why it is used regularly by organic and non-organic growers. It is a decision that you, as a grower, need to make whether yield reductions can be justified based upon labor and disposal savings with a biodegradable mulch.
The two studies in Resources below list the specific mulch type alternatives and the results of their field trials. Also, the ATTRA publication Season Extension Techniques for Market Gardeners may give you some alternative production techniques that can alleviate the need for plastic mulch, such as hoop house, or high tunnel, production.
Miles, Carol. Alternatives to Plastic Mulch for Organic Vegetable Production. CSANR Organic Cropping Research for the Northwest. Research Progress Report.
Downloaded Sept. 2006.
Rangarajan, Anu, Betsy Ingall and Mike Davis. Alternative Mulch Products 2003. Cornell University horticulture Department. 2003.
Peaceful Valley Farm Supply
P.O. Box 2209
125 Clydesdale Court
Grass Valley, CA 95945
Order Toll Free (888) 784-1722
They have a lot of alternative paper and poly mulch products.
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