Agron. Sustain. Dev. 26 (2006) 241-249
DOI: 10.1051/agro:2006022

The CropSyst model to simulate the N balance of rice for alternative management

Roberto Confalonieri^a, Davide Gusberti^b, Stefano Bocchi^b and Marco Acutis<sup>b

a</sup>  Institute for the Protection and Security of the Citizen, Joint Research Centre of the European Commission, AGRIFISH Unit, MARS-STAT Sector, TP 268 - 21020 Ispra (VA), Italy
^b  Department of Crop Science, Section of Agronomy, University of Milano, Via Celoria 2, 20133 Milano, Italy

(Accepted 22 August 2006; published online 23 January 2007)

Abstract - CropSyst is a mechanistic model developed for simulating the growth and development of potentially all herbaceous crops under potential and water/nitrogen (N)-limited conditions. Although the model has been widely used for many crops under different pedo-climatic and management conditions, studies on the simulation of water and N balance for flooded rice are lacking. We evaluated the CropSyst model for simulating the N balance of north-Italian rice fields for scatter-seeded rice grown under continuously flooded conditions. In order to calibrate and validate the model for the processes involved with soil N transformation, data collected in field experiments carried out in northern Italy between 2002 and 2004 were used. The results show the robustness of the model in reproducing the course of the measured soil mineral nitrogen content: the Modeling Efficiencies which describe the agreement between measured and simulated trends, are in most cases positive and the model error fell almost always within the experimental error on the measurements (P = 0.95). Moreover, the model showed the same level of reliability while simulating the nitrogen balances under different levels of nitrogen fertilization, thus depicting it as suitable for comparing N fertilization scenarios. This first attempt at using a model for simulating the nitrogen balance under flooded conditions encourages further studies because of the need of effective tools for optimizing the nitrogen management of flooded rice systems, considered significant sources of groundwater pollution and greenhouse gases in many European rice districts.

Key words: Oryza sativa L. / simulation model / flooded soil / submerged fields / nitrogen transformation / mineralization / denitrification

Corresponding author: Roberto Confalonieri roberto.confalonieri@jrc.it

© INRA, EDP Sciences 2006