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Title: Effects of foliar potassium fertilization on muskmelon fruit quality and yield

item Lester, Gene

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/23/2009
Publication Date: 6/16/2009
Citation: Jifon, J.L., Lester, G.E. 2009. Effects of foliar potassium fertilization on muskmelon fruit quality and yield [abstract]. HortScience. 44(3):566.

Interpretive Summary:

Technical Abstract: Consumer preference of many fruits and vegetables such as muskmelon [Cucumis melo L. (Reticulatus Group)] is determined by a few key quality traits such as sugar content, aroma and texture. These quality traits are directly related to adequate potassium (K) content in plant tissues. However, soil-derived K alone is seldom adequate to satisfy these fruit quality processes. Controlled environment studies have shown that supplemental foliar K applications can mitigate this apparent deficiency. However, the suitability of potential K salts as foliar sources is still uncertain. We evaluated six foliar K sources (potassium chloride - KCl, potassium nitrate – KNO(3), monopotassium phosphate – Peak, potassium sulfate – K(2)SO(4), potassium thiosulfate – KTS, and a glycine amino acid-complexed K- Potassium Metalosate, KM) for effects on fruit quality parameters of field-grown muskmelon (cv ‘Cruiser’) over two growing seasons, 2006 and 2007 in Weslaco, south Texas. Weekly foliar K applications were initiated at fruit set and continued to fruit maturity. Although soil K concentrations were very high, supplemental foliar K treatments resulted in higher K concentrations in plant tissues, suggesting that plant K uptake from the soil solution was not sufficient to saturate tissue K accumulation. In 2006, fruit yields were not affected by supplemental foliar K spray but in 2007, yields differed significantly among the foliar K sources with treated plots generally having higher yields than the control plots. Fruit from plots receiving supplemental foliar K had higher external and internal fruit tissue firmness than control fruit and this was associated with generally higher soluble solids concentrations (SSC) in both years. All the foliar K sources studied had positive effects on fruit quality parameters except for KNO(3) which tended to result in less firm fruit with lower SSC values. These results demonstrate that the apparent K deficiency caused by inadequate uptake can be alleviated by supplemental foliar K applications and that the effectiveness of foliar K fertilization will depend, not only on the source of fertilizer K, but also on environmental conditions affecting soil K availability and overall plant growth and development.