Microlysimeter sketch, B. Church
The Global Microlysimeter Network provides a dataset of N leaching dynamics in conjunction with local weather data to crop, soil or agro-ecosystem modellers. Global coverage of major soil–climate combinations assures that models will be made fit-for-purpose for ubiquitary simulations of N mineralisation as a precondition of successful predictions of crop growth and N emissions across environments.
Microlysimeters provide an easy-to-simulate soil system section that give clue to the amount of nitrogen being released from stabilised organic matter in agriculturally used soils over time. As no plant is involved, there is no need to care for root N uptake and its capture for N balancing. However, plant-induced stimulation of organic matter turn-over cannot be captured. Provided sufficient water drainage, the shallow dimension of the microlysimeter assures a timely leaching of the mobile N compounds soon after their formation. In periods of a negative water balance, mineral N compounds will stay where they are, largely unaltered, and leach during the next rainfall event. This is a pattern that agro-ecosystem models should be able to mimic and inverse modelling should be able to find mineralisation parameters that fit the cumulative outflow of mineral N from the microlysimeter soil.