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PERSPECTIVE

CSU Spring, 2005, Vol. 13, No. 2, p. 87

Needed: Compost Tea Research Findings

A TRIO of reports on compost tea in the June 2005 issue of BioCycle, Journal of Composting & Organics Recycling, verifies the need for research to advance knowledge in this field. The first report - written by a vineyard manager at a Napa Valley, California winery - describes how wine-grape farming is helping to close the large gap between the practice and the science of compost tea. The author

explains how he spreads solid compost at the rate of one to four tons per acre, while he applies compost tea at ten gallons per acre. Based on his observations, the tea applications supply his plants with nutrients that are “alive with microbes, their metabolic by-products and also help to prevent and suppress plant diseases.” But, continues the grower: “I will continue using it in my own agricultural endeavors, but without dedicated study, it will only exist as a generalist technology. I know that the potential of compost tea is great but that with more research and knowledge on this important subject, all of humanity could benefit.”
The second report by a compost consultant provides information on how Suffolk County, New York public golf courses have begun to experiment with compost teas on small areas of their courses. “One major stumbling block is the lack of understanding of just how the microbial communities of compost and soil function.” A two-year project has begun, funded by the New York State Department of Economic Development, to demonstrate and refine biological techniques on golf courses.
As part of a study funded by the Sustainable Agricultural Research program and the Organic Farming Research Foundation, technical staff at The Rodale Institute conducted field trials in 2003 and 2004 to evaluate compost tea use. They concluded that while the potential value exists, benefits are inconsistent and “no panacea.” Further scientific research is needed, their studies indicated, to improve understanding of the process. James Travis, Penn State fruit pathologist, assisted with experimental design and disease monitoring in the Pennsylvania vineyards. Also working on the project was Alice Wise, a Cornell Cooperative Extension viticulture expert based near a vineyard in New York State. After working intensively with compost tea for the past two years, the Institute staff “believe it has potential to become a useful component of an integrated crop improvement program. Its benefits are inconsistent however. …Compost tea requires further scientific research to clarify its potential benefits and to improve understanding of biological cropping system improvement strategies.”
The July, 2005 issue of BioCycle - sister publication to this journal - will report on the compost tea trials of Dr. Lynne Carpenter-Boggs of Washington State University's Crops and Soils Science Department. In her paper, she refers to the challenge of critics who point out the scarcity of convincing studies and the potential for microbiological hazards. “Both are legitimate concerns that can only be addressed by more education and research under strict guidelines. Several studies,” she cites, “have successfully controlled plant diseases and increased plant growth with compost teas. …The issue of microbiological safety must be taken seriously, and should be addressed in a fashion similar to potentially hazardous food preparation activities like canning and krauting. …In making compost tea, a high quality finished compost or inoculant is absolutely necessary.”
Adds Carpenter-Boggs: “With tens of thousands of home brewing machines already sold in the U.S., compost tea is not going away anytime soon, and should be addressed seriously by agricultural institutions and agencies. The responsible answer is to study and recommend recipes and methods that preserve human safety but allow freedom for specialized products.”
As is the case with so many critical areas in organics recycling, solutions reflect the cooperation of scientists, industry and persistent, knowledgeable users. - J.G.