Simulation of soil mineral nitrogen dynamics in banana cover-cropping systems on andosol with the BANANA-N model

The use of organic nitrogen (N) fertilizer and cover crops offer a potential alternative to the synthetic N fertilization in banana cropping systems. However, these changes in cultural practices alter the availability of mineral N and could result in a loss in yield in these agrosystems. Our objective was to develop a model based on existing models specific to banana cultivation to simulate soil mineral N in agroecological banana agrosystems on andosol. BANANA-N integrated several modifications: the simulation of atmospheric N fixation by legume cover crops, simulation at mat scale to take account of stand heterogeneity, and subdivision of the soil into two layers to better match the functioning of andosols. Then, the model was evaluated by comparing observed and simulated soil mineral N dynamics in banana cropping systems with contrasting N fertilization management. Although model formalisms imply simplifying assumptions, BANANA-N performs well in predicting above ground banana biomass with contrasting N fertilization management (0.27 ≤RRMSE≤0.42 and 0.7 ≤NSE≤0.86). The soil mineral nitrogen dynamics were fairly well predicted in sole cropping or intercropping with a grass plant (0.33 ≤RRMSE≤0.46), while it was poorly predicted when banana is grown in association with a leguminous plant (RRMSE≥0.53). This study presents the first calibration of the BANANA-N model, capable of assessing the impact of different fertilization strategies on banana productivity, and their potential contribution to maximize internal N recycling and minimize N losses to the environment.