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Subject

Potassium

Description

Potassium deficiency: green color fading from leaf margins.

Compared to nitrogen fertilization, potassium (K) fertilization needs are far less frequent in vineyards. Reasons for this include the more steady supply of K provided by soil minerals, the depth of many vineyard soils, and the resistance of K to losses from leaching. When vines are deficient, however, the vine symptoms and crop effects can be dramatic. On the other hand, an overabundance of K is of no benefit to the vine or the crop.

You can easily detect a K deficiency by watching for leaf symptoms. These symptoms usually appear in midsummer as a fading of green color at the leaf edges and between the main veins. The leaf margins tend to curl upward and become necrotic. Mild deficiencies will not show until late summer, approaching harvest. Severe deficiencies may appear around bloom and may ultimately affect most of the leaf area with chlorosis in addition to leaf margin necrosis.

People

Doug Adams
L. Peter Christensen
Donna Hirschfelt
William L. Peacock
Rhonda Smith
Larry Williams

Publications

Adams, D.O., Franke, K.E. and Christensen, L.P. 1990. Elevated putrescine levels in grapevine leaves that display symptoms of potassium deficiency. Am. J. Enol. Vitic. 41:121-125. Abstract

Christensen, L.P. 1975. Long-term responses of 'Thompson Seedless' grapevines to potassium fertilizer treatment. Am. J. Enol. Vitic. 26:179-83. Abstract

Christensen, L.P. 1984. Nutrient level comparisons of leaf petioles and blades in twenty-six grape cultivars on three years, 1979-1981. Am. J. Enol. Vitic. 35:124-33. Abstract

Christensen, L.P. 2000. Mineral Nutrition and Fertilization (PDF). Pages 102-114 in: Raisin Production Manual. University of California, Agricultural and Natural Resources Publication 3393, Oakland, CA. Buy book

Christensen, L.P., Boggero, J., and Bianchi, M.L. 1990. Comparative leaf tissue analysis of potassium deficiency and a disorder resembling potassium deficiency in 'Thompson Seedless' grapevines. Am. J. Enol. Vitic. 41:77-83. Abstract

Christensen, L.P., Kasimatis, A.N., and Jensen, F.L. 1978. Grapevine nutrition and fertilization in the San Joaquin Valley. University of California Division of Agricultural Science, Publication 4087, Berkeley, CA.

Christensen, L.P., Peacock, W.L., and Bianchi, M.L. 1991. Potassium fertilization of 'Thompson Seedless' using two fertilizer sources under drip irrigation. Am. J. Enol. Vitic. 42:227-32. Abstract

Kasimatis, A.N., and Christensen, L.P. 1976. Response of 'Thompson Seedless' grapevines to potassium application from three fertilizer sources. Am. J. Vitic. 27:145-49. Abstract

Williams, L.E., Biscay, P.J., Smith, R.J. 1987. Effects of interior canopy defoliation on berry composition and potassium distribution of 'Thompson Seedless' grapevines. Am. J. Enol. Vitic. 42:118-22. Abstract

2004. Soil Environment and Grapevine Mineral Nutrition Symposium. Proceedings of the American Society of Enology and Viticulture. To Purchase

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