On our farm... totally depends on the analysis of the manure.   

We have three types of manure.   Hog manure from confinement barns.   Sawdust-bedded manure from cattle.  And cattle liquid manure from an outdoor pit.   Three totally different kinds of manure with vastly different nutrient contents. 

We've been yearly sampling these three types of manure.  We typically use the averages thereof to decide how much to apply to each field, giving due respect to the amount of nutrients the fields already have prior to the manure applications.  

Be careful building your phosphorus levels to good to very high levels.   We've noticed a significant yield hit when we get phosphorus levels out of whack with zinc levels.  As our phosphorus levels go up, we need to up our zinc levels.   We try to maintain a 10 to 1 ratio of phosphorus to zinc.  Seems to be the sweet spot for us.


gordon