Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/2008
Publication Date: 9/7/2008
Citation: Vaughn, S.F., Tisserat, B., Deppe, N.A., Berhow, M.A. 2008. Tomato yield responses to soil-incorporated dried distillers grains [abstract]. Association for the Advancement of Industrial Crops Conference. p. 22.
Technical Abstract: Dried distiller's grains (DDGs) are a coproduct of dry-grind corn ethanol production, most of which are used for animal feed, and are sold for under $150/metric ton. Developing higher-value uses for DDGs can increase the profitability of corn-based ethanol. Although DDGs applied directly to a potting medium were phytotoxic to several ornamental plants (Boydston et al., 2008), preliminary studies with incorporating DDGs into soil and allowing it to decompose for a short period of time (~1 month) indicated that it could promote plant growth of several test species, including tomatoes. In addition, solvent-extractable compounds such as oil, phytosterols and tocopherols present in DDGs are being evaluated for value-added uses, while the extraction step also eliminates most of the fermentation odor of the DDGs. DDGs were obtained from Big River Resources, LLC, Burlington, IA. DDGs were Sohxlet-extracted with anhydrous ethanol to obtain extracted-DDGs (X-DDGs). N-P-K values for DDGs and extracted DDGs were 4.1-0.9-1.4 and 6.0-2.0-1.7, respectively. Cottonseed meal (CSM) was used as an organic control as its N-P-K values were 6-2-1, similar to the values of the DDGs. All three amendments were added to a silt loam soil at the rate of 1 kg/m2 into 2 m X 1.5 m blocks and incorporated to a depth of 15 cm on April 15, 2007. The experiment utilized a Latin Square design with four replicates with a nonamended control treatment. Four six-week-old tomato (Solanum lycopersicum L. 'Health Kick') plants were planted in each block on May 15, 2007. Plots treated with all three amendments exhibited no offensive odors at any time during the experiment. Tomato plants treated with both types of DDGs exhibited accelerated growth responses for the initial month compared to either the controls or the cottonseed meal treatments. Initial tomato harvests were on July 15, 2007 and continued until October 25, 2007. Numbers of fruit per plant averaged 107, 143, 145, and 136 for controls, CSM, DDGs and X-DDGs treatments, respectively, with all three treatments being significantly higher than the control. Total yields averaged 8.6, 11.3, 11.6, and 10.6 kg/plant for controls, CSM, DDGs and X-DDGs treatments, respectively, with all three treatments being higher than the control, and the DDGs and CSM treatments significantly higher than the X-DDGs. These results indicate that unextracted DDGs offer excellent potential as an organic fertilizer for tomatoes.