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Title: Petiole, N, P, K concentrations and yield of the potato cultivar Molli from certified organic amendments and fertilizer formulations

Author
item Collins, Harold - Hal
item Porter, Lyndon
item Boydston, Rick
item Alva, Ashok
item CHAVEZ, BERNARDO - Washington State University

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2016
Publication Date: 8/20/2016
Publication URL: http://handle.nal.usda.gov/10113/63205
Citation: Collins, H.P., Porter, L., Boydston, R.A., Alva, A.K., Chavez, B. 2016. Petiole, N, P, K concentrations and yield of the potato cultivar Molli from certified organic amendments and fertilizer formulations. Communications in Soil Science and Plant Analysis. 47(10):1227-1238.

Interpretive Summary: Organic production systems have been shown to modify soil and improve nutrient cycling with the addition of organic amendments and organic-formulated fertilizers. This study evaluated the petiole uptake of N, P, K and S by the potato variety Molli from organic sources and fertilizer formulations under an irrigated certified organic production system in 2011 and 2012. Amendments evaluated included: two seed meals, mint compost and five commercially available organic fertilizers compared to a vetch/rye cover crop. Tuber yields were not statistically different between fertilized treatments averaging 53 Mg ha-1. Although there was high variability among fertilizer formulations, any of the fertilizers evaluated would be sufficient to supply potato with additional nutrition. This study provides organic potato growers baseline information on the performance of a diverse array of organic fertilizers and amendments.

Technical Abstract: Organic production systems have been shown to modify soil and improve nutrient cycling with the addition of organic amendments and organic-formulated fertilizers. This study evaluated the petiole uptake of N, P, K and S by the potato cultivar Molli from organic sources and fertilizer formulations under an irrigated certified organic production system in 2011 and 2012. The experimental design was a complete randomized block consisting of eight organic fertilizer amendments, applied at a 280 kg N ha-1 equivalent. Amendments evaluated included: two seed meals, mint compost and five commercially available organic fertilizers compared to a vetch/rye cover crop. Analysis showed that available soil NO3-N and NH4-N from each amendment averaged 115 kg N ha-1 at application and 25 kg N ha-1 at 30 d after planting through harvest in August, with minor differences between fertilizers or amendments in both years. Petiole N declined from an average of 25,000 mg N kg-1, 4 weeks after emergence to 3,000 mg N kg-1 prior to vine kill and harvest, with the lowest levels observed for the ROmint compost and non-fertilizer treatments. Petiole P and K concentrations were maintained above 4000 mg P kg-1, 10,000 mg K kg-1, and 2000 mg S kg-1 tissue, respectively, throughout the growing season in all treatments. Tuber yields were not statistically different between fertilized treatments averaging 53 Mg ha-1. This study provides organic potato growers baseline information on the performance of a diverse array of organic fertilizers and amendments.