Sensitivity analysis of CSM-CERES-MAIZE to field capacity in simulation of nitrogen fate

Subject Areas : Farm water management with the aim of improving irrigation management indicators

Rahele Malekian ¹ , Mahdi Gheysari ²

1 - PhD student, Water Engineering Department, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
2 - Assistant Professor, Water Engineering Department, College of Agriculture, Isfahan University of Technology, Isfahan, Iran

Received: 2011-05-11 Accepted : 2011-10-27 Published : 2012-03-02

Keywords: Ammonium, Crop modeling, DSSAT, nitrate leaching,

Abstract :

CERES is a family of crop-soil-atmosphere models which is a component of the DSSAT, can successfully simulate N budget of the crop-soil system and also different N management scenarios. Field capacity (FC) is one of the important parameters of soil-water-crop-atmosphere models which the accurate measurement of this parameter is very expensive and time consuming. In this study the sensitivity of the CSM-CERES-Maize model to FC in simulation of soil nitrate and ammonium concentration in different soil layers, and plant N uptake was evaluated. The study was performed using the experimental data obtained from the field study conducted on silage maize in 2003 and 2004 at the south of Tehran, Iran. The treatments were four irrigation levels of 0.7, 0.85, 1 and 1.13 soil moisture depletion with three fertilizer levels (0, 150, and 200 kg N ha-1). The results showed that the percentage change of simulated soil nitrate concentration was between 7.17 and 96.75 due to 25% change of FC (either increase or decrease). This value for simulated soil ammonium concentration was between 33.31 and 139.01. The CERES model was sensitive to FC changes in simulation of soil nitrate and ammonium concentrations and its sensitivity was different in soil layers. This model was little sensitive to FC changes in simulation of mineralization, nitrification, and plant N concentration. Overall the results revealed that an exact determination of FC can reduce uncertainty in simulation of soil nitrate and ammonium concentration using the CERES model.