Evaluation of a Dynamic Agroecosystem Model (Agro-IBIS) for Soybean in Southern Brazil

Abstract

With the growing demands for food and biofuel, new technologies and crop management systems are being used to increase productivity and minimize land-use impacts. In this context, estimates of productivity and the impacts of agriculture management practices are becoming increasingly important. Numerical models that describe the soil–surface–atmosphere interactions for natural and agricultural ecosystems are important tools to explore the impacts of these agronomical technologies and their environmental impacts. However, these models need to be validated by considering the different soil and environmental conditions before they can be widely applied. The process-based terrestrial agricultural version of the Integrated Biosphere Simulator (IBIS) model (Agro-IBIS) has only been calibrated and validated for North American sites. Here, the authors validate the Agro-IBIS results for an experimental soybean site in southern Brazil. At this site, soybean was grown under two different management systems: no tillage (NT) and conventional tillage (CT). The model results were evaluated against micrometeorological, soil condition, and biomass observations made during the soybean growing season. The leaf area index (LAI) was underestimated, approaching the values obtained in the CT crop system, with higher error in the leaf senescence period. The model shows higher skill for daily averages and the diurnal cycle of the energy balance components in the period of high LAI. The soil temperature and moisture were robustly simulated, although the latter is best correlated with the observations made at the CT field. The ecosystem respiration is highly underestimated, causing an overestimation of the cumulative net ecosystem exchange (NEE), particularly at the end of the crop cycle.

Reliable, robust and realistic: the three R's of next-generation land-surface modelling

“…Further new developments include consideration of the relevance of agriculture, wetlands and lakes for the aggregate behaviour of the land surface (e.g. Rosnay et al, 2003;Ringeval et al, 2012;Webler et al, 2012;Drewniak et al, 2013). With these aspects adding ever-increasing complexity, however, a new modelling strategy is required to ensure that the uncertainties do not spiral out of control as more and more uncertain parameters are introduced.…”

Effects of Land Use Change for Crops on Water and Carbon Budgets in the Midwest USA

“…Kucharik et al (2000) validated the performance of Agro-IBIS comprehensively through comparing the model simulation with global-scale observations of water balance and carbon balance [18]. Agro-IBIS has been used to evaluate corn yield against field observations and USDA census data across the USA Corn Belt [16,20,21] and soybean yield in Brazil [22], as well as to evaluate the crop growth, daily net ecosystem productivity, and ecosystem respiration against measurements at an Ameriflux site [23]. The model has been used to explore crop production and nitrate export in the Mississippi River basin [24,25], river discharge and seasonal and interannual variations in water balance [26,27], and environmental issues related to switchgrass and miscanthus production for bioenergy [12,13,28].…”

Influence of Soil Properties in Different Management Systems: Estimating Soybean Water Changes in the Agro-IBIS Model

“…Previous studies, such as Kucharik and Twine (2007) and Webler et al (2012), described an overestimation of LAI simulation in phase 3. The original equation for LAI in the Agro-IBIS model for phase 3 is LAI 5 LAI " 1 2 gdd plant 2 hui grain 0:55gdd maturity…”

“…More details about the experimental design can be found in Webler et al (2012) and Moreira et al (2015).…”

“…The soil is represented by 11 layers totaling 2.5 m in depth. The Agro-IBIS model was calibrated and validated for soybean for conditions in North and South America (Kucharik and Twine 2007;Twine et al 2013;Webler et al 2012). …”