%X Vegetable cropping systems are prone to high nitrogen (N) leaching losses. Optimizing the management of each crop can reduce this problem, but not solve it. Important improvements in cropping system N efficiency can be obtained by improving the rotation, to make sure that N left by some crops are to a large extent used by the succeeding crops. However, this includes rotation and fertilization planning based on a complex set of information on many crop species, on catch crops and green manure crops and on their interaction with soil and weather conditions. Simulation models can be used in various ways to give specific advice for growers on fertilization. Models can also be used to help growers develop their growing systems by helping them to get a better understanding of the strong and weak points of their rotations in terms of N use efficiency, and on the consequences of alternative choices or management. %L orgprints16318 %J Acta Horticulturea - Towards ecologically sound fertilization strategies for field vegetable production %A Kristian Thorup-Kristensen %T Nitrogen use efficiency in organic and conventional vegetable rotations.: Measured and model simulated results %P 71 %D 2008