Temperatures Differ Between Fronts and Backs of Shaded and Sunlit Berries

Abstract

Close-focus pyrometers were employed to measure temperatures among blackberry fruits at sunlit and shaded locations on static and one-sided shift trellises with westward leaning (20 to 25° from vertical) crop support arms. About 85% of the static trellis' fruits were located on its eastern face while essentially all of the shift trellis' berries were westward-oriented. During cloudless weather, east-facing berries at 9:30 am were 5 to 8 °C warmer than either ambient air or berries on western trellis faces. West-facing berries were at or near air temperature until 2 or 3 pm; east-facing berries remained above air temperature until 4:30 or 5 pm. Temperatures at the sunlit sides of healthy, east-facing `Arapaho' berries averaged 8 °C warmer than at shaded sides of the same berries.