Modelling leaching losses from grazed systems

Leaching losses from grazed systems are notoriously hard to measure and to model because they are primarily generated from the deposition of urine patches and are therefore very spatially variable. Researchers from AgResearch in New Zealand have validated the ability of APSIM to predict leaching from urine patches in grazed systems and some of that work has been presented at the annual Fertilizer and Lime Research Centre Workshop “Adding to the Knowledge Base for the Nutrient Manager” earlier this year. Papers presented include work on leaching losses from urine patches, pre-experimental modelling on the interaction of fertiliser and urine patches, and nitrification inhibitors to reduce leaching.