The best way to measure the efficiency of your spread is by calculating the co-efficient of variation (CV) using a tray test. This will assess not only the fertiliser spreading capacity but also the effectiveness of your spreader.

The lower the CV value, the better: A CV of over 15% will result in financial loss as it will be detrimentally affecting soil fertility and crop performance, now and in the long term.

But when testing CV you need to keep one thing in mind: It’s easier to test the CV of a CCF product as it is a true measure of how even each nutrient is being spread. But for a blend, you may see a low overall CV which might indicate a good spread pattern, but it can mask high CV’s for individual nutrients.