Impact of potassium nutrition on postharvest fruit quality: Melon (Cucumis melo L) case study

• Published in: Plant and soil 2010-10, Vol.335 (1-2), p.117-131
• Main Authors: Lester, Gene E, Jifon, John L, Makus, Donald J
• Format: Article
• Language: English
• Subjects: Acid soils; Agricultural site preparation; Agrology; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; application timing; Autumn; Beta carotene; Bioactive compounds; Biological and medical sciences; Biomedical and Life Sciences; Case studies; chemical constituents of plants; Consumer behavior; Cucumis melo; Ecology; Environmental factors; Fertilization; Fertilizers; foliar application; Fruit; fruit composition; fruit quality; fruiting; Fruits; fruits (food); Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Glycine; human health; Hydroponics; Life Sciences; Marketability; melons; Nitrogen, phosphorus, potassium fertilizations; nutrient uptake; Nutrients; Nutrition; Orchard soils; Phytochemicals; plant nutrition; Plant Physiology; Plant Sciences; Plants; postharvest treatment; Potassium; Potassium fertilization; potassium fertilizers; preharvest treatment; REVIEW ARTICLE; Salts; Soil fertility; soil nutrients; Soil Science & Conservation; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; Spring; Sugar; sugars; Surface active agents; vitamins; yields
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-009-0227-3

Among the many plant mineral nutrients, potassium (K) stands out as a cation having the strongest influence on quality attributes that determine fruit marketability, consumer preference, and the concentration of critically important human-health associated phytonutrients. However, many plant, soil, and environmental factors often limit adequate uptake of K from the soil in sufficient amounts to satisfy fruit K requirements during development to optimize the aforementioned quality attributes. The objectives of this review are 1) to summarize published study abstracts on the effects of soil and/or foliar K fertilization as well as diverse K forms, on fruit phytonutrient concentrations; and 2) to illustrate the important role of K forms on fruit quality with a case study of Cucumis melo L (muskmelon) fruit produced with optimal soil applied K . The muskmelon studies will compare commercial sources (forms) of K applied to examine seasonal effects (spring vs. autumn) and the number of foliar K applications during fruit development on fruit marketability (maturity, yield, firmness, soluble solids, sugars, relative sweetness), consumer preference attributes (sugar content, sweetness, texture), and phytochemical concentrations (K, ascorbic acid, and β-carotene concentrations). Numerous studies have consistently demonstrated that specific K fertilizer forms, in combination with specific application regimes, can improve fruit quality attributes. Potassium fertilizer forms in order of effectiveness (Glycine (Gly)-complexed K = K₂SO₄ ≥ KCl > no K > KNO₃) when applied wet (foliar or hydroponic) vs. dry (soil) were generally superior in improving fruit marketability attributes, along with many human-health nutrients. The muskmelon case study demonstrated that two K forms: Gly-complexed K and K₂SO₄, combined with a silicone-based surfactant, applied weekly, as a foliar spray, during fruit development, from both autumn and spring-grown plants, had the greatest impact on improving fruit marketability attributes (maturity, yield, firmness, and sugars), as well as fruit quality attributes (human-health bioactive compounds K, ascorbic acid, and β-carotene). Among several foliar applied K salts studied under field conditions so far, salts with relatively low salt indices appeared to have the greatest impacts on fruit quality when applied during the mid- to late-season fruit development periods.