Bermudagrass Carbohydrate Levels as Influenced by Potassium Fertilization and Cultivar
- Grady L. Miller and
- Ray Dickens
Stored nonstructural carbohydrates are a primary source of reserve energy in vegetative organs of warm-season grasses. Research is needed concerning the influence of potassium on carbohydrate levels in turfgrasses. Four K rates ranging from 24 to 390 kg ha−1 per growing month were applied twice monthly from 1992 to 1994 to ‘Tifdwarf’ and ‘Tifway’ bermudagrasses [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy] field grown on Uchee loamy sand (loamy, siliceous, thermic Arenic Hapluduit) and sand-peat (9:1 by volume) dium. Root + rhizome and shoot + stolon samples were evaluated monthly for total non-structural carbohydrate (TNC) concentrations by means of near infrared reflectance spectroscopy. TNC concentrations varied among cultivars, plant parts, and time of year. Tifdwarf produced 30% greater root + rhizome TNC concentration and 55% greater shoot + stolon concentration than Tifway. Higher K rates either did not influence or reduced root + rhizome TNC concentrations compared to low K rates. Correlation analysis indicated that root + rhizome yields and TNC concentrations were negatively influenced by temperature. Carbohydrate and root + rhizome yield responses suggesthere is no benefit to applying K at rates beyond those that provide sufficient K levels for normal growth.
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