Calibration of the century, apsim and ndicea models of decomposition and n mineralization of plant residues in the humid tropics

Abstract

SUMMARYThe aim of this study was to calibrate the CENTURY, APSIM and NDICEA simulation models for estimating decomposition and N mineralization rates of plant organic materials (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum, Stylosanthes guyanensis) for 360 days in the Atlantic rainforest bioma of Brazil. The models´ default settings overestimated the decomposition and Nmineralization of plant residues, underlining the fact that the models must be calibrated for use under tropical conditions. For example, the APSIM model simulated the decomposition of the Stizolobium aterrimum and Calopogonium mucunoides residues with an error rate of 37.62 and 48.23 %, respectively, by comparison with the observed data, and was the least accurate model in the absence of calibration. At the default settings, the NDICEA model produced an error rate of 10.46 and 14.46 % and the CENTURY model, 21.42 and 31.84 %, respectively, for Stizolobium aterrimum and Calopogonium mucunoides residue decomposition. After calibration, the models showed a high level of accuracy in estimating decomposition and N-mineralization, with an error rate of less than 20 %. The calibrated NDICEA model showed the highest level of accuracy, followed by the APSIM and CENTURY. All models performed poorly in the first few months of decomposition and N-mineralization, indicating the need of an additional parameter for initial microorganism growth on the residues that would take the effect of leaching due to rainfall into account.Index terms: legumes, nutrient cycling, organic farming, plant production.

Calibration and validation of models for short-term decomposition and N mineralization of plant residues in the tropics

“…To simulate accurately the decomposition of plant residues of organic material, the parameter that controls the decomposition process in Century and APSIM was calibrated so as to decrease decomposition (Table 4), such as observed by Nascimento et al (2011) to calibrate the same models to decomposition and N-release for 360 days. In the calibrated models, this reduction of the default value of the parameter of Century and, more markedly for APSIM, suggested high sensitivity of the models to prevailing environmental conditions (Addiscott, 1995).…”

“…More details and other input variables for the models are shown in Table 2. Model equations and further details can be found in Keating et al (2003), Nascimento et al (2011), Parton et al (1994 and Van de Burgt et al (2006). After model parameterization, calibration was performed to ensure that observed and predicted values matched observed data by modifying pertinent model parameters for each model.…”

“…The study developed by Nascimento et al (2011) indicated the difficulty of the models to estimate the decomposition and N mineralization in short-term. So, the purpose of this study was to evaluate the ability of the Century, APSIM and NDICEA simulation models to correctly predict the decomposition and subsequent N release rates of crop residues in the tropical Atlantic forest biome.…”

Decomposição e liberação de N, P e K de esterco bovino e de cama de frango isolados ou misturados

“…elevados de C e N e com menores valores das relações C/N, lignina/N e polifenóis/N são decompostos mais rapidamente (Moreira & Siqueira, 2006;Vanega Chacón et al, 2011;Nascimento et al, 2011).…”

“…Tais processos são influenciados pela qualidade dos resíduos (teores e relações entre C, N, P, S, lignina, celulose e polifenóis), pela atividade da biota e pelas condições edafoclimáticas (pH, textura, umidade, temperatura e aeração do solo) (Eghball et al, 2002;Moreira & Siqueira, 2006;Nascimento et al, 2011;Vanega Chacón et al, 2011).…”