Problem. Having a properly functioning and calibrated fertiliser spreader ensures optimum return on investment and minimises environmental impact. The co-efficient of variation or CV (how evenly fertiliser is spread across a field) should ideally be under 10%. Solution. When calibrating a spreader, you will want to check a few vital things. the fertiliser spreader is level both front to back and side to side on the tractors 3-point linkage and that the stabiliser bars are tight. That the fertiliser veins move freely, and the bearings are in proper working order to ensure there is no play or uneven movement on their axis of rotation and that the agitator located inside the spreader is working correctly. Next measure the flow rate by removing one of the discs and running the machine for 30 seconds while collecting the fertiliser it dispenses in a bucket. Weigh this bucket and compare the weight with the fertiliser spreader manufacture guidelines. Measure the height of the fertiliser spreader either above ground or above the crop to ensure that we are meeting the manufactures working height guidelines.