To save time and money most of you prefer to straight cut your wheat, barley, rye or oats. The allow for straight cutting the crop has be evenly ripe across the field and the straw and grain has to be dry enough that it will feed through the combine.
Waiting for a whole field to dry down poses a risk for the portion of the field that is already harvest ripe, including sprout damage, straw breakage and lodging. To even out dry-down and/or speed up dry-down you have two basic options. Swathing or windrowing, at one time, was the default operation that signaled the beginning of harvest. A second preharvest option is an application of glyphosate at the hard dough stage.
Glyphosate is labeled as a harvest aid to control late emerged weeds that may interfere with harvest. The RoundUp PowerMax II label doesn't define it as a desiccant. Research has shown that glyphosate applied with or without ammonium sulfate may hasten drydown of the wheat crop if conditions for drydown are adverse. With a preharvest interval of 7 days, a couple of days, at the most, may be gained. Previous Minnesota Crop News post provide details about
swathing and
preharvest glyphosate.