Check for potash
SILAGING grass removes four times as much potash as phosphate, yet often the potash is not replaced.
John Hollies of the Potash Development Association said too little potash was returned to soils reducing efficiency of nitrogen use.
An incredible amount of slurry or manure is needed to redress the imbalance between phosphate and potash. He recommended soil testing every four years to ensure fertiliser applications were accurate.