Modelling of earthworm population dynamics in agricultural soils (First draft)

Earthworms are known to play a role in the nitrogen mineralisation in agricultural soils. Here we present simulations of the population dynamics of two earthworm species that are dominating in danish arable land, and compare the simualtions with observed densities (number and biomass) of the two species from three fields in Denmark. The simulations show an acceptable fit to the observations. The simulation model is used to quantify the impact of the observed earthworm populations on the minearalisation of nitrogen and in turn the crop production. The simulations show an increase in yield due to the earthworm contribution to mineralisation, and that the earthworms can be responsible for about 1/3 of the biologically mineralised nitrogen.