The diurnal cycling of sugars in grasses impact strip-graze management plans

Soluble sugar concentrations increase in forage plants during the day and decrease at night. The objective of this study was to quantify the sugar concentrations in the upper and lower parts of the grass canopy at the end of a light and subsequent dark period and relate these changes in animal grazing behavior and production responses. Tall fescue (Festuca arundinacea) grown in controlled-environment chambers was cut after a 15-h light and a subsequent 9-h dark period, and tillers were separated into leaves and stems. Leaves, but not stems, demonstrated diurnal fluctuation in sugars. Leaf sugars concentrations, after 15-h of light, were 1.6 times greater than those in leaves following the 9-h dark period. It is suggested that animal production may benefit from afternoon vs. morning turnout onto fresh pastures because of the extra sugars accumulating in the leaves during the day