A method of controlling the downpressure on an air seeder that has a plurality of seed assemblies and a plurality of fertilizer assemblies each applying an adjustable downforce, wherein the method includes keeping a total downforce applied by all of the plurality of seed assemblies and all of the plurality of fertilizer assemblies less than a maximum downforce. The method may also include keeping the downforce applied by each of the fertilizer assemblies less than the downforce applied by each of the seed assemblies.
