BANANA-N: a dynamic model to simulate nitrogen balance in agroecological banana cropping systems

Organic nitrogen (N) fertilization and the introduction of cover crop could be an alternative to the use of synthetic nitrogen fertilizers in banana cropping systems. But changing agricultural practices modify nitrogen bioavailability in the agrosystem and may ultimately decrease crop yield. Our aim was to design a simple dynamic model to simulate nitrogen balance of banana cropping system in association with a cover crop and organic fertilization over successive crop cycles. This study presents the general structure and formalisms of BANANA-N mainly based on SIMBA-N model and validated models in scientific literature. BANANA-N simulates nitrogen dynamic at a weekly time step in banana agrosystems. It includes six sub-models: cover crop N uptake, banana N uptake, N leaching, soil organic matter mineralization, crop residue mineralization and added organic matter mineralization. Volatilization and denitrification of nitrogen were not included in the model because they are insignificant in andosols. Two main improvements were integrated in the model to take into account N mineralization from added organic matter and cover crop uptake. Moreover, nitrogen flows in field soil are simulated in two distinctive horizontal layers (0-30, 30-60 cm). BANANA-N was developed to run in a tropical climate context on andosol for the ‘CIRAD 925’ cultivar over three crop cycles. Evaluation of the model showed that it accurately simulated the aboveground biomass of banana and cover crops with contrasting fertilizer management. These first results demonstrate the use of BANANA-N model in developing fertilization management strategies for designing sustainable banana cropping systems.