Drying Rates of Standing Compared to Windrowed Wheat 1

Little information is available to support the practice in the northern USA and Canada of windrowing wheat to accelerate grain drying. Drying rates of standing and windrowed wheat ( Triticum aestivum L. and T. turgidum var. durum L.) were compared at three locations in western Canada in order to assess the efficacy of windrowing in accelerating the wheat harvest. The soil was an Aridic Haploboroll. The time taken for wheat windrowed at recommended kernel water concentrations of 430 to 540 g water per kg kernel dry weight to reach a safe water concentration (170 g kg −1 ) for combining was compared with the time taken for the standing crop to reach this point. In 40 station‐years data, windrowed wheat dried from 6 days faster to 1 day slower than standing wheat. In all but 4 station‐years, windrowed wheat dried 0 to 2 days faster than standing wheat. Under hot, dry conditions, drying rates of both standing and windrowed crops were very rapid, with a 0‐ to 1‐day spread in drying time. When crop maturity was uneven and drying conditions less favorable, windrowed wheat reached the combining stage up to 6 days faster than standing wheat. Wet conditions during harvest caused slower drying of windrowed than of standing wheat. Light rains tended to cause greater increases in kernel water concentrations of standing than of windrowed wheat. Straw dried faster than kernels in windrowed crops, but slower than kernels in standing crops.