On arable farms Phosphorous is essential for high yielding crops. It is essential for fruit and seed production through its role in the cell membrane and in genetic structures. However recently concerns have grown regarding decline of global P supplies, increasing P fertiliser prices which threaten future food production and the loss of P to the wider environment. The application method and timing of P fertiliser in arable applications has also shown to affect the P fertiliser use efficiency increasing uptake and reducing P losses through leachate. Since P is not very mobile in the soil under low soil test P levels plants must increase their root density. On the majority of Irish farms most P fertiliser is broadcast onto the soil surface and then incorporated at sowing. This seems to be work for soils with relatively high STP levels (index 3 and 4). However, in low STP situations the soil can lock up much of this P fertiliser in a relatively short time. Research has shown that placing the P fertiliser with the seed at sowing in spring barley is the most efficient way to reach target yields.