Pot Trial - How can soil structure influence phosphorus availability ?

Phosphorus (P) is a natural element used by all living organism. Under the Water Framework Directive ~40% of Irish rivers currently exceed target P concentrations. Altered fertiliser practices have achieved limited reduction of P excess. Current recommendations are based predominantly on fertiliser application, and soil chemistry. This project shifts the focus to include the influence of soil physical properties on P mobilisation. While previous research indicates the effect of soil texture on P dynamics, a knowledge gap exists regarding the influence of structure on P dynamics. The first study, a pot trial, compares the influence of contrasting soil structures on build-up and draw down of soil P, across low to high P indices. The hypothesis is that poor soil structure impedes change in P index and mobilisation of P reserves. Soil physical quality will be assessed at the conclusion of the pot trial in 2025. Precise laboratory methods using the latest advances in soil physics equipment will be used to assess the soil physical quality. Traditional methods were an arduous undertaking, limited by lack of data points, and could take several months to complete. The latest additions of HYPROP 2 devices to the SETU laboratories allows this information to be collected over a few days. The automated instrument produces more data points at higher resolution, giving precise soil physical properties details. The addition of soil physics equipment to SETU laboratories allows unparalleled accuracy, automation, faster measuring speeds, and a greater analysis capacity in the area of soil physics research. The increasing technical capacity in the area of soil physics, aligns with the continuing advances in soil chemistry and biology. It is anticipated that the results of this work will indicate if structural variations influence the manipulation of soil test P levels and mobilisation of P reserves.