are the greatest problem facing California rice. They must be dealt with
early or the weeds will take over the field and little rice will be
produced. Growers use a variety of methods to apply weed control materials
as can be seen here: airplanes, special spray rigs, or even small spray rigs
pulled by four-wheelers.
Growers make choices on their application method based on many factors. Some weed control materials can only be applied with ground based equipment. How much water is in the field, what weeds are being targeted, how fast the application is needed, and what equipment is available - all these factors come into the decision process.
One of the great stories about rice is that these materials are applied early in the growth of the rice. Another 40 days or so after application will pass before the seed structure will even come out of the rice plant. Harvest is 80 days or more away when these materials are sprayed. The natural process built into weed control sprays is that they will degrade over time - most of them in a fairly short time. So when weed control application comes at the usual time, the rice grain is not exposed to these materials.