To test the accuracy of ryegrass mapping using satellite imagery.

Picking out the ryegrass from the cereal crops in spring did not prove to be effective.The ryegrass tiller count data was converted into a contoured map and divided into three zones for each paddock. Once again we compared the manually drawn zones and found a relatively good correlation but not good enough to mplement patch ryegrass management with confidence. A dual boom A more detailed analysis of previous yield maps when farmers determine their ryegrass patches would certainly improve the accuracy of their zone drawings. Any farmer wanting to implement patch ryegrass management should also consider btaining imagery at a time of the year when ryegrass is more visible such as prior to sowing or around crop establishment as these maps would more accurately define the weed patches with less crop effect.