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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Functional Foods Research » Research » Publications at this Location » Publication #303862

Title: Evaluation of potato anaerobic digestate as a renewable alternative to peat moss in horticultural substrates

item Vaughn, Steven
item LEE, E - Summit Seed, Inc
item WAGNER, R - Microbial Energy Systems Inc

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/27/2014
Publication Date: 7/31/2014
Citation: Vaughn, S.F., Lee, E., Wagner, R.E. 2014. Evaluation of potato anaerobic digestate as a renewable alternative to peat moss in horticultural substrates [abstract]. Potato Association of America.

Interpretive Summary:

Technical Abstract: Potato peels and other low-value wastes from potato processing are currently being used as cattle feed or fermented to produce fuel-grade ethanol. The anaerobic fermentation of food wastes, including potato processing wastes, produces biogas (principally methane), which can be used directly for heating or for the production of electricity. After fermentation is complete a wet digestate remains, which after drying was found to have physical characteristics similar to peat moss. This led to our evaluation of the dried digestate as a peat moss replacement in horticultural potting substrates. Physical and chemical properties of the digestate were in the desired ranges for potting substrates. As a starter substrate (for tomato, marigold and basil seed germination), the digestate alone or 1:1 with vermiculite performed as well or better than 1:1 peat/vermiculite with or without added chemical fertilizer. Three transplant substrate formulations were also tested: 100% digestate; 1:1 digestate/vermiculite; and 1:1 peat/vermiculite. All three treatments received a slow-release chemical fertilizer and dolomitic limestone. Three-week-old tomato and marigold seedlings were transplanted into pots (2.5 L) containing each of the formulations. Changes in plant heights and dry weights were measured after 4 weeks. Growth of both species for both substrates containing potato digestate was equal to or superior to plants grown in 1:1 peat/vermiculite. These results indicate that potato anaerobic digestate could be an excellent renewable replacement for peat moss in horticultural substrates.