A large percentage of the fields planted to cotton in the San Joaquin Valley of California are treated with a dinitroaniline herbicide and listed or "bedded up" and followed with a pre-irrigation during late fall and winter, 3 to 4 months previous to planting. Volunteer cereals and certain broadleaf winter annuals, especially those in the mustard family, are not controlled by the dinitroaniline herbicides and will grow on the beds. These weeds can deplete the available soil moisture and interfere with final seedbed preparation.

The present approach to controlling this unwanted vegetation is the use of either aerial applied paraquat or glyphosate (Roundup). Although this system has been successful the possibility of drift to non target crops is of concern. Mechanical cultivation is also used, but due to wet weather and soil conditions this practice is not always feasible. Labor and fuel cost, due to the number of cultivations required, and soil compaction also limit this practice.