ARS | Publication request: Residual effects of fresh and composted dairy manure applications on potato production

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 2, 2011
Publication Date: June 8, 2011
Citation: Moore, A.D., Olsen, N.L., Carey, A.M., Leytem, A.B. 2011. Residual effects of fresh and composted dairy manure applications on potato production. American Journal of Potato Research. Available: http://www.springerlink.com/content/ek7858uj37088r50/fulltext.html.

Interpretive Summary: Potato growers in Idaho and other dairy producing regions often grow potatoes on fields that have had a history of fresh and composted manure applications. Growers remain uncertain of the impacts that previous manure applications will have on tuber yield and quality, as well as diseases, physiological disorders, and contamination by human pathogenic bacteria such as E. coli. The focus of this study was to determine the long term effects of manure, compost, and chemical phosphorus fertilizer applications on tuber yields, tuber quality, nutrient uptake, tuber disorders and diseases, and soil nutrient concentrations. Russet Burbank potatoes were grown in 2008 and 2009 on plots that had received dairy manure, dairy compost, phosphorus fertilizer, or no phosphorus source (control) at the same target phosphorus rate in 2003, 2004, and 2005. Compared with the phosphorus fertilizer treatment, applications of manure and/or compost significantly increased total yields, soil potassium, soil nitrate, early season petiole phosphorus, and late season petiole potassium in at least one year of the two-year study. There were no significant differences between phosphorus fertilizer, manure, and compost treatments on soil test phosphorus, late season petiole phosphorus, early season petiole potassium, E. coli populations on tuber surfaces, common tuber diseases and disorders, and tuber quality. Based on our findings, it appears that the impact of fresh and composted dairy manure application after 3 or more years on potato crop yields is greater than has been reported by other authors in production regions outside of Idaho. The most obvious causes for improved yields appear to be the concentrations of potassium and nitrate in the soil from the manure and compost sources, although there may be other factors that were not measured that may also be improving the yield potential. In contrast, our findings also suggest that the impact of fresh and composted dairy manure after 3 or more years of application on potato tuber quality, diseases, and disorders is less than previously reported. Comparing manure and compost treatments to fertilizer only treatments, there was no significant effect on any of the parameters measured, including E. coli populations, specific gravity, common scab, black scurf, silver scurf, pink eye, pink rot, dry rot, vascular discoloration, brown center, tuber malformation, glucose, sucrose, and fry color. When working with soils that have a manure or compost history, our findings suggest that it may be more reliable to use preplant soil test nitrate and potassium concentrations instead of petiole values for predicting tuber yield. Conversely, petiole phosphorus values during tuber set may be better than soil test phosphorus values or late season petiole phosphorus values for predicting yield.

Technical Abstract: Potato growers in Idaho and other dairy producing regions often grow potatoes on fields that have had a history of fresh and composted manure applications. Growers remain uncertain of the impacts that previous manure applications will have on tuber yield and quality, as well as diseases, physiological disorders, and contamination by human pathogenic bacteria such as E. coli. The focus of this study was to determine the long term effects of manure, compost, and chemical phosphorus (P) fertilizer applications on tuber yields, tuber quality, nutrient uptake, tuber disorders and diseases, and soil nutrient concentrations. Russet Burbank potatoes were grown in 2008 and 2009 on plots that had received dairy manure, dairy compost, P fertilizer, or no P source (control) at the same target P rate in 2003, 2004, and 2005. Compared with the P fertilizer treatment, applications of manure and/or compost significantly increased total yields, soil potassium (K), soil nitrate (NO3-N), early season petiole P, and late season petiole K in at least one year of the two-year study. There were no significant differences between P fertilizer, manure, and compost treatments on soil test P, late season petiole P, early season petiole K, E. coli populations on tuber surfaces, common tuber diseases and disorders, and tuber quality. Based on our findings, tuber yields significantly increased three years after applications of fresh and composted dairy manure, while tuber diseases, disorders, and quality were not affected.