Organic Reactive Phosphate Rock- RPR
RPR has a citric solubility of around 45%. Essentially a supplier of phosphorus, RPR releases both calcium and phosphorus to the soil at a rate determined by the natural activity of worms and microbes. Containing significant quantities of calcium, RPR also contains trace minerals that enhance life both above and below the ground.
As a result of increased biological activity plants grown are stronger and less prone to attack and damage by flea, weevil, or any other predator. In the case of clover this means more nitrogen fixed naturally. Given the extensive trial work conducted by MAF here in New Zealand growers can confidently switch from conventional suppliers of phosphorus to RPR. Where sulphur is a requirement, elemental sulphur (equally as effective and often more efficient) can be added to ensure maximum dry matter performance.
Used as a maintenance fertiliser, Pasture development, Pasture growth
RPR is typically applied at rates of 100 to 300 kg/ha although actual spreading rates will vary according to climate, farm type, productivity and soil type; ideally soil pH should be less than 6.