The effect of nitrogen rate on vine kill, tuber skinning injury, tuber yield and size distribution, and tuber nutrients and phytonutrients in two potato cultivars grown for early potato production

Authors: Boydston, Rick; Navarre, Duroy - Roy; Collins, Harold; CHAVES-CORDOBA, BERNARDO - Washington State University

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2017
Publication Date: 3/31/2017
Citation: Boydston, R.A., Navarre, D.A., Collins, H.P., Chaves-Cordoba, B. 2017. The effect of nitrogen rate on vine kill, tuber skinning injury, tuber yield and size distribution, and tuber nutrients and phytonutrients in two potato cultivars grown for early potato production. American Journal of Potato Research. 94:425-436. doi:10.1007/s12230-017-9579-z.

Interpretive Summary: Early potatoes are typically produced by harvesting tubers much earlier (in approximately 10 weeks after planting) compared to full season potatoes. Early potatoes require less nitrogen inputs as high nitrogen rates can delay tuber set and lead to excessive vine growth that is more difficult to terminate prior to harvest. Three preplant soil nitrogen levels 34 to 38, 67, and 101 kg N ha-1 were tested on Bintje and Ciklamen potato cultivars in 2013 and 2014 near Paterson, Washington. Nitrogen rate had little impact on the number of tubers and stems per plant of both cultivars, but increasing nitrogen rate tended to increase canopy leaf area making vine desiccation more challenging. Tuber skinning injury, tuber weight loss, and tuber size distribution were not affected by nitrogen rate. Tuber skinning injury and tuber weight loss in storage were reduced in both cultivars by delaying harvest until four weeks after initial vine desiccation. Total tuber yield was lower for both cultivars in one of two years at the lowest nitrogen rates (34 to 38 kg N ha-1). Tuber nitrogen and zinc levels tended to increase with increasing nitrogen rates, while most other nutrients, vitamin C, total phenolics, and antioxidant capacity showed little response. A nitrogen rate of 67 kg N/ha was adequate to produce a good tuber set and yield of small tubers while not producing excessive vine growth that may be more difficult to kill.

Technical Abstract: Early potatoes are typically produced using less nitrogen than a full season potato crop as high rates of nitrogen may delay tuber set and lead to excessive vine growth that is difficult to terminate prior to harvest. Bintje and Ciklamen potato cultivars were grown with preplant soil nitrogen levels of 34 to 38, 67, and 101 kg N ha-1 in 2013 and 2014 near Paterson, Washington. Nitrogen rate had little impact on the number of tubers and stems per plant of both cultivars, but increasing nitrogen rate tended to increase leaf area of both cultivars. Vine desiccation of Bintje with diquat was less complete as nitrogen rate increased, while Ciklamen vine kill was reduced by higher nitrogen in one of two years. Tuber skinning injury, tuber weight loss, and tuber size distribution were not affected by nitrogen rate. Tuber skinning injury and tuber weight loss were reduced in both cultivars by harvesting at four weeks after initial vine kill compared to harvesting at two weeks after vine kill. Total tuber yield was lower for both Bintje and Ciklamen in one of two years at the 34 to 38 kg N ha-1 rate. Tuber nitrogen and zinc levels tended to increase with increasing nitrogen rates, while most other nutrients, vitamin C, total phenolics, and antioxidant capacity showed little response. It appears that 67 kg N/ha provides adequate nitrogen to produce a good tuber set and yield of small tubers while not producing excessive vine growth that may be more difficult to kill.