The model assumes that production and inputs are in balance, and that within the nutrient budget, inputs equal outputs. To balance the nutrient budget, either immobilisation or N fixation is adjusted as these are modelled with the least confidence. On blocks with 'low' N inputs but high N removal, for example as supplements, this can result in elevated clover fixation levels. It could also indicate that soil N is being mined, and hence the block setup may not be sustainable.
Why do I sometimes see high clover fixation?
