No one uses Round Up on a field days before harvest. The author is an idiot.
Yeah, brand name Round Up is way too expensive. Today's commercial farmers use non-branded versions of Glyphosate.
It's applied to grain crops days before harvest as an incentive for the plants to put their last bit of energy into increasing the size of the grains - especially soybean and wheat crops. And it's been standard practice for quite a number of years now.
Glyphosate is used to top kill and dessicate grain and soybean crops before harvest. I understand why farmers do it, but am not thrilled by the practice.
In fact, Monsanto representatives promoted this as a way to increase harvest. I posted a link from the Wayback Machine a few years ago... from the Monsanto website.
I do not know if anyone still does it.