Calibration and test of the cropgro-dry bean model for edaphoclimatic conditions in the savanas of Central Brazil

Abstract

Simulation models are important tools for the analysis of cultivated systems to estimate the performance of crops in different environments. The CROPGRO-model (DSSAT) was calibrated and validated using Carioca bean (Phaseolus vulgaris L.) to estimate yield and the development of the crop, sown in three row spacings (0.4, 0.5, and 0.6 m) and two fertilization rates (300 and 500 kg ha -1 of 4-30-16 N-P-K), in Santo Antônio de Goiás, GO, Brazil. To calibrate the model a combination of the genetic coefficients that characterize the phenology and morphology of the dry bean crop was used to obtain the best possible fit between predicted and observed anthesis and physiological maturity dates, leaf area index (LAI), total dry matter (TDM), yield components, and grain yield for the 0.6 m row spacing. To test the model the experimental records of the 0.4 and 0.5 m row spacings were used. In both, calibration and test, the performance of the model was evaluated plotting observed and predicted values of LAI and TDM versus time, using the r 2 , and the agreement index (d) as statistical criteria. In relation to yield and yield components the percent difference between the observed and predicted data was calculated. The model appeared to be adequate to simulate phenology, grain yield and yield components for the Carioca bean cultivar, related to different levels of fertilization and row spacing, either during calibration or the testing phase. During the test, the grain yield was overestimated by less than 15.4%, indicating a potential use for the calibrated model in assessing climatic risks in this region. Key words: DSSAT, dry bean, simulation CALIBRAÇÃO E TESTE DO MODELO "CROPGRO-DRY BEAN" PARA AS CONDIÇÕES EDAFOCLIMÁTICAS DO BRASIL CENTRALRESUMO: Modelos de simulação são importantes ferramentas na análise de sistemas cultivados para estimar a performance da cultura em diferentes ambientes. O modelo CROPGRO-foi calibrado e testado, utilizandose o cultivar Carioca para estimar a produtividade e o desenvolvimento do feijoeiro (Phaseolus vulgaris L.) sob três espaçamentos (0,4, 0,5 e 0,6 m) e duas doses de adubação (300 e 500 kg ha -1 de 4-30-16 de N-P-K), em Santo Antônio de Goiás, GO. A calibração consistiu na modificação dos coeficientes genéticos característicos da fenologia e morfologia do feijoeiro, visando obter os melhores ajustes possíveis entre os dados simulados e os observados a campo das datas de antese e maturação fisiológica, índice de área foliar (IAF), massa de matéria seca total (MMST), componentes de produção e produtividade de grãos para o espaçamento de 0,6 m. Para o teste do modelo foram utilizados os dados experimentais correspondentes aos espaçamentos de 0,4 e 0,5 m. Em ambos, calibração e teste, a aferição da performance do modelo foi efetuada plotando-se os valores observados e simulados do IAF e MMST ao longo do tempo (dias após semeadura), e utilizando-se o r 2 e o índice de concordância (d) como critério estatístico. Para produtividade de grãos e componentes de produção determinou-se a di...

The performance of the CROPGRO model for bean (Phaseolus vulgaris L.) yield simulation

“…In addition, the RMSE was low (2.47%). These results are consistent with previous studies that showed that the model appeared to simulate the phenology of the bean cultivars adequately (FARIA et al, 1997;MEIRELES et al, 2002). …”

Calibration and Testing of Cs-Cropgro Model for Common Beans

“…The flowering was estimated as 54 days after sowing (DAS), the onset of the first pod as 61 DAS and the physiological maturity as 96 DAS. Other studies had already proved the ability of this model in simulating the phenology of other cultivars of beans, corroborating our findings (MEIRELES et al, 2002;OLIVEIRA et al, 2012). (Figure 3).…”

“…In another study, DALLACORT et al (2005) studied different planting dates of beans, and observed a maximum LAI of 3.34 m 2 m -2 during the best growing season. However, these results are lower than those observed by MEIRELES et al (2002), who found IAFs of up to 6.47 m 2 m -2 in simulations.…”

Modelling the role of agriculture for the 20th century global terrestrial carbon balance

“…Using these values worldwide leads to overestimated yields in regions with more extensive management. Extensive management characterized by low fertilizer inputs leads generally to reduced canopy growth and lower LAI (Meireles et al , 2002). As the model presently contains no explicit nutrient cycles, we proxy these processes by adapting the LAI max value to the fertilizer use level for two dominant CFTs: temperate cereals and maize.…”