Evaluation of a process-based model for the estimation of nitrogen losses in a flooded rice system

Amat Sadikin, Muhammad Khairil Fahmier (2019) Evaluation of a process-based model for the estimation of nitrogen losses in a flooded rice system. [Project Paper] (Submitted)

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Abstract

Simulation of nitrogen (N) losses by using a mathematical model in flooded rice system is important for designing and developing protocols for the management of crop nutrients to ensure sustainable production. Objective for this study are to select an appropriate process-based model for simulation purpose and to test the performance of the model against secondary data sets, and a mathematical model proposed by Liang’s was chosen in order to estimate N losses from urea applied in a flooded rice system. However, as a first step, the performance of this model in quantifying N losses must be evaluated. N transformations namely, urea hydrolysis, volatilization, nitrification, denitrification and N transportations like runoff, lateral seepage, vertical leaching and crop uptake were consider in this study. The secondary datasets from Xu et al., (2018) that consist of observed ammonia volatilization, ammonium (NH4+) left in soil solutions and nitrate (NO3-) left in soil solutions were used to evaluate the model’s performance. This model underwent parameter calibration three times. Results showed that the observed ammonia volatilization were well predicted by this model, but not for NH4+ and NO3- left in soil solutions. The model simulation values were not exactly same as the observation values for NH4+ left in soil solutions and NO3- left in soil solutions. The performance of this model in identifying NH4+ and NO3- beneath soil surface is still poor.

Item Type:	Project Paper
Faculty:	Faculty of Engineering
Depositing User:	Ms Siti Mariam Giman
Date Deposited:	17 Nov 2022 01:33
Last Modified:	17 Nov 2022 01:33
URI:	http://psaspb.upm.edu.my/id/eprint/532

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