Spring 1995 (v7n2)
The Urban/Agricultural Recycle Connection
Farmers, gardeners and scientists are familiar with recycling. They know that using microorganisms such as bacteria and fungi as decomposers is key to the recycling of organic material. Linking rural and urban wastes and using the composting knowledge found on farms may be a way to help us "get out from under" the problem of our waste disposal and make society, as well as agriculture, more sustainable.
Although all systems generate waste, some wastes are easier to manage than others. The management of waste from modern industrial systems is becoming more complex and expensive as landfills reach capacity. Noting this, the California Legislature passed the Integrated Waste Management Act (AB 939) in 1989, which gave communities responsibility for waste reduction and recycling. The bill required that by 1995, 25 percent of a community's total solid waste stream must be diverted from landfills through source reduction, recycling and composting. According to officials at the California Integrated Waste Management Board (CIWMB), that goal will be met. California cities, like those throughout the nation, have increased their recycling efforts. The City of Davis last year recycled 36 percent of its waste, Lodi recycled 32 percent, while San Jose diverted 45 percent of its residential waste from landfills.
Howard Levenson, a CIWMB staff member, notes that the Integrated Waste Management Act's second goal, to reduce waste by half by the year 2000, will be a challenge for local governments, California businesses, consumers and the CIWMB. He said the focus will be on waste prevention (i.e., helping businesses reduce waste while saving money, and increasing backyard composting), and developing greater markets for materials such as yard and wood debris, paper, plastics, and construction and demolition debris. The 28 percent of the waste stream that can be composted-yard, food and wood waste-may be used on farms.
In order to stimulate composting markets for urban waste, the CIWMB has funded five two-year compost/mulch demonstration projects. Projects selected involve cooperative teams working in Fresno, Tulare, Stanislaus, Santa Cruz and Santa Clara counties on the use of composted orchard, cotton, grape and vegetable residue. Each team is comprised of farm operators, UCCE farm advisors and other technical experts, compost/mulch processors, and representatives of local government. Participating farm advisors and UC researchers include Harry Andris, Fresno County; Carol Frate, Tulare County; Craig Kolodge, Santa Clara County; Jesus Valencia and Ed Perry, Stanislaus County; and Marc Buchanan, UC Santa Cruz. The goal is to promote the use of municipally derived mulch or compost in commercial agriculture. Information from the projects won't be available until the end of 1996, but enthusiasm is high. Additionally, other farm advisors throughout the state are involved in waste management projects funded by the California Department of Food and Agriculture.
Since California soils are characteristically low in organic material, it is hoped that these projects will show that the following benefits can be obtained from compost products: increased soil organic matter; greater numbers of soil microbes; better soil moisture retention; a decrease in the leaching of soil nutrients; and a reduced need for commercial fertilizer to sustain crop reduction.
Agriculture is also continuing to find new ways to recycle its own wastes. Until recently, for example, almond processors were able to sell most of their almond shell waste to biomass power plants. However, almond processors are now receiving lower returns from shell sales due to changing regulations in both the electrical utility and waste management sectors. Faced with this situation, processors representing a significant portion of the industry have contracted with agAccess Information Service in Davis to identify and evaluate potential alternative uses for shells. Such uses may include direct application as a mulch in orchards and vineyards, and as a compost when combined with poultry or livestock waste. On a related note, increasing numbers of farmers are leaving prunings in the orchards and chipping them on site, eliminating the need for burning.
Animal agriculture systems in California are also big contributors of organic waste material. Manure from the state's animal production totals 250 million pounds per day from approximately 300 million animals, according to UC Davis Animal Systems Management Specialist Jim Oltjen. At a recent conference on the impact of animal agriculture on California water quality, several speakers noted that California livestock operations are larger and more concentrated than in other states, and our limited water supplies make this an important agriculture waste issue (See "Agricultural Animals and California's Water," page 5.) Farmers, ranchers and regulators are working to find creative solutions for potentially valuable manure waste.
Various sectors of society will play different roles in our efforts to manage wastes. For many industries, the important component of waste management may be reducing waste. For agriculture, it may be composting its own waste, and also finding ways to use the composted organic wastes of urban dwellers. Identifying the ways each of us can best manage waste may represent the critical thin line that determines whether or not we're sustainable.-Bill Liebhardt, director, University of California Sustainable Agriculture Research and Education Program.
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