The Dahlen Long Term Fertilizer Experiment was established by Incitec Pivot Fertilizers in 1996. It has four rates of P (0, 9, 18 and 36 kg P/ha) combined factorially with 5 rates of N (0, 20, 40, 80, 160 kg N/ha), with the N applied at either sowing or split between sowing and early growth. The crops are selected as part of a normal cropping rotation in this region which takes the general form of canola, wheat, barley and then a pulse (chickpea, lentil or field pea). Soil test nutrient levels, grain yield and quality are assessed along with nutrient removals to develop indices of nutrient removal and soil test changes.