Reduced nitrogen leaching by intercropping maize with red fescue on sandy soils in North Europe: a combined field and modeling study.

Aim: To study maize ( Zea mays L.) growth and soil nitrogen (N) dynamics in monocrop and intercropped systems in a North European climate and soil conditions with the support of a simulation model. Methods: Field data for 3 years at two sites/soil types in Denmark and three main factors: (i) cropping history (maize or grass-clover), (ii) maize monocrop or intercropped with red fescue ( Festuca rubra L.) and (iii) three fertilizer N rates, were used to calibrate and validate the DAISY model for simulation of crop growth and soil N dynamics. Field and model results were used to study the treatment effects on the maize systems. Results: Intercropped maize had 15-37 % lower N leaching than monocrop maize. Maize intercropping following a maize crop was achieved without yield loss at the standard N rate or higher, while red fescue offset N leaching. Maize intercropping following grass-clover needed less N, thereby greatly reducing the N leaching. Conclusions: The hypothesis that maize intercropping with fertilizer N rates applicable to monocrop maize decreases N leaching without significant yield loss was largely supported given the effect of cropping history and soil type. The applicability of DAISY was extended to provide better analyses of intercropping systems and complex management options to reduce N leaching across northern Europe. [ABSTRACT FROM AUTHOR]