ARS | Publication request: Effects of Foliar Potassium Fertilization on Muskmelon Fruit Quality and Yield

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 10, 2008
Publication Date: January 20, 2008
Citation: Jifon, J.L., Lester, G.E. 2008. Effects of foliar potassium fertilization on muskmelon fruit quality and yield. Meeting Proceedings. Albion Conference on Plant Nutrition, Midway, Utah. p. 8-36.

Technical Abstract: Sugar content, aroma and texture are key quality traits that influence consumer preference of many fruits and vegetables such as muskmelon [Cucumis melo L. (Reticulatus Group)]. These quality traits are directly related to potassium (K)-mediated processes. 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 overcome this apparent deficiency. However, the suitability of potential K salts as foliar sources is still uncertain. We studied the effects of six foliar K sources (potassium chloride – KC1, potassium nitrate – KNO3, monopotassium phosphate – MKP, potassium sulfate – K2SO4, potassium thiosulfate – KTS, and a glycine amino acid-complexed K – Potassium Metalosate – KM) on fruit quality parameters of field-grown muskmelon ‘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 pre-plant 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 the tissue K accumulation. In 2006, fruit yields were not affected by supplemental foliar K sprays, but in 2007, yield 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 concentration (SSC) in both years. All the foliar K sources studied had positive effects on fruit quality parameters, except for KNO3, which tended to result in less firm fruit lower SSC values. The results are consistent with previous controlled environmental findings that supplementing soil K supply with foliar K applications during fruit development and maturation can improve muskmelon fruit quality by increasing SSC, firmness, and sugar contents.