Manures and slurries contain readily available nutrients that can be used as alternatives to bagged fertiliser.
However in order to use manures and slurries at the best rate possible, you need to know what they contain and then reduce bagged fertiliser accordingly.
The best way of knowing the nutrient content of manures is to have them analysed regularly. The following information is based on the average nutrient content of slurry for a range of dry matter contents.