Foam markers for use on boom sprayers - Agriculture Western Australia. By Ed Blanchard, Agricultural Engineer, Farm Machinery Unit, Merredin When using a boom spray, an effective marking system is essential to prevent overlapped and unsprayed areas.
Any overlap increases chemical use and time taken and hence the cost of the spraying operation.
The higher chemical application rate also increases the selection pressure in the area of overlap, hastening the development of herbicide resistance. Unsprayed areas decrease crop yields from that area of the paddock and can increase seed set of weeds and the weed burden in future years. Foam markers are used on most boomsprayers to mark the edge of the sprayed areas. Producing good quality foam Water quality It is best to use rainwater to make foam, preferably water warmer than 12 C. Contaminants including salt and other minerals have a big effect on the quality of the foam produced. If bore water is used, the sulphur content can be lowered by letting the water stand in an open drum for at least 24 hours.