How profitable are herbicides for weeds in crops?

BEFORE spending money on chemical weed control in crops, a farmer needs to know how profitable the operation will be. He may also be influenced by other things such as the need for weed-free seed, but the most important consideration should be an increased cash return. If a herbicide is used to control weeds in a crop, the extra yield achieved must be worth more than the cost of the herbicide and its application for the treatment to be profitable. This article gives guidelines to help farmers estimate the likely profitability of herbicide treatments for quota and non-quota crops