Gary L. Wade & Wayne J. McLaurin, Extension Horticulturists
Now, more than ever, "The environment is our business." Recent environmental legislation is having a pronounced effect on the way Green Industry professionals do business.
Since 1990 and the passage of Georgia's Comprehensive Solid Waste Management Act, landfills across the state have been diverting organic plant materials in a effort to meet a 25 percent reduction in volume required in 1996. Since organic plant materials (leaves, grass clippings, and prunings) account for 18 to 20 percent of the solid waste stream, municipalities see diversion as one of the most immediate and easy ways of achieving the required 25 percent reduction. Many municipalities are stockpiling organic plant materials brought into the waste disposal facility. Some local governments have purchased grinders or chippers to chip woody material and are using the chips as landfill cover. Others are hiring service companies to grind the woody material periodically. Most municipalities generally don't want to deal with organic material and are increasing tipping fees to compensate for higher management costs.
In 1994, Georgia's state government passed House Bill 257, an amendment to the 1990 Solid Waste Management Act. It states that as of September, 1996, organic plant materials are banned from disposal facilities having liners and leachate collection systems requiring vertical expansion. Other landfills that continue to receive these materials must sort, grind, recycle or compost these materials. In other words, they must be managed not stockpiled. Again, these increased management costs result in higher tipping fees.
All this means that, in the future, Green Industry professionals will have to find a use for discarded plant debris (trimmings, grass clippings, dead plants, etc.) and used soil media by recycling them on their own property and by re-using them in their businesses. Let's explore the options available to Green Industry professionals for dealing with these materials:
Land Application: Applying degradable organic materials, such as leaves, grass clippings and used soil media and chipped woody brush, to the soil surface is perfectly acceptable. In many northern states, it is common practice for farmers to receive organic materials as land application and to disk them into the soil periodically to improve soil tilth. Some firms supply the farmer with dolomitic lime as needed in return for his use of the organic materials.
Mulch: Chipped woody brush and shredded leaves make an excellent mulch for adding back to the landscape. Although they may not be as visually attractive as pine bark or pine straw, shredded leaves and chipped wood provide all the benefits of mulch and are particularly useful in the more low-profile areas of a landscape, such as a wooded area seen from a distance. These materials may also be used as a base under more visually appealing mulches to reduce costs.
Low-Tech Composting: Local authorities will not allow firms to simply stockpile these materials indefinitely. If they do, local and state authorities may consider the property a landfill and may apply laws and ordinances accordingly. The local fire marshall will also get involved when stockpiled woody brush appears to be a fire hazard. Therefore, organic materials must be managed in some way, such as grinding stockpiled woody brush once (preferably twice) a year. (The law is not clear as to how often you must grind or what volume stockpiled is acceptable.) In some areas, a tree service company may be hired to chip the woody materials. Some firms may also rent or purchase a grinder or chipper ($10,000 to $20,000). The decision whether to hire someone to grind the materials or to rent or buy a grinder will depend on the volume of materials being generated.
Low-level composting involves placing organic materials in piles not more than 10 feet high and about 10 feet wide, then turning them occasionally (perhaps once a month) with a front-end loader. Avoid building the pile higher than 10 feet; it will pack down and undergo anaerobic decomposition, which produces odors. Instead, expand the length of the pile, not the height, to form a window.
The best mixture of organics for decomposition is 30:1 carbon to nitrogen ratio (more simply, three parts browns - leaves, chipped brush- to one part green - fresh green trimmings, grass clippings). Livestock manure can be added as a nitrogen source when greens are not available (fall leaf season, for instance). Livestock manure also serves as an inoculate to help speed decomposition. Nitrogen fertilizer, such as ammonium nitrate, can also be used to increase the nitrogen content of the pile. Broadcast two cups of ammonium nitrate over each cubic yard of leaves.
Locate the pile near a water source, so you can add moisture during dry periods. Materials during decomposition should have the consistency of a wrung-out sponge -- not too wet or too dry.
Compost is an excellent soil amendment provided is well decomposed. One to three inches of compost applied to the soil surface and incorporated into the top 10 inches will result in a 10 percent to 30 percent increase in organic matter, an ideal level for improving soil tilth. Unfinished, undecomposed organics used as a soil amendment will cause a rapid drop in soil pH and nutrient deficiency as micro-organisms utilize nitrogen from the soil to decompose the organic materials.
The regulatory agency on composting is the Environmental Protection Division, Land Protection Branch of the Georgia Department of Natural Resources (404-362-2537). According to officials at DNR, as long as the compost made is used back on the property of the owner or on properties managed by the owner, the compost is not sold, and the composting operation presents no threat to surrounding ground water via run-off, no permits or fees are required. Technical information regarding the composting procedure can be obtained through local county Extension offices.
Thomas, W.A., W.J. McLaurin and G.L. Wade. A Guide for Municipal Composting of Organic Landscape Refuse. Ag. Econ. Publication 91-005. Cost $5/copy from Extension Agricultural Economics, University of Georgia, Athens, GA 30602.
Thomas, W.A., W.J. McLaurin and G.L. Wade. A Guide to Organizing and Promoting a Community Composting Program. Ag. Econ. Special Report 233. Cost $3/copy from Extension Agricultural Economics, University of Georgia, Athens, GA 30602.
McLaurin, W.J. and G.L. Wade. Composting and Mulching: A Guide to Managing Organic Landscape Refuse. Georgia Cooperative Extension Service Circular 816. Free from your local county Extension agent.
McLaurin, W.J. and G.L. Wade. Feed Your Landscape: Not the Landfill. A series of three fact sheets on composting, mulching and grasscycling. Excellent for home audiences. Camera-ready copies available free from Extension Horticulture, 224 Hoke Smith Building, University of Georgia, Athens, GA 30602.
McLaurin, W.J. and G.L. Wade. Home Composter Handbook. A 200-page reference notebook discussing home composting from A to Z. Guidelines for establishing a community composting program. Available for $20 from Extension Horticulture, 224 Hoke Smith Building, University of Georgia, Athens, GA 30602.
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