Ontology-based simulation of water flow in organic soils applied to Florida sugarcane

Agricultural Water Management (Impact Factor: 2.29). 01/2010; 97(1):112-122. DOI: 10.1016/j.agwat.2009.08.019
Source: RePEc


An ontology-based simulation (OntoSim) is a unique data modeling environment where soil-plant-nutrient processes are represented as database objects and the user-defined relationships among objects are used to generate computer code (Java) for running the simulation. The aim of this study was to model hydrologic processes of sugarcane-grown organic soils utilizing OntoSim in the Everglades Agricultural Area (EAA) of South Florida. This OntoSim-Sugarcane model describes the complex hydrology of sub-irrigation and open ditch drainage commonly used on Florida farms. Model calibration was conducted by (i) selecting rectangular farm water management units (<12ha), which are encompassed with farm ditches, from two farms in the EAA, (ii) assembling all relevant input data including water tables (WT) recorded at the monitoring farm well of each unit, and (iii) optimizing the fits between the simulated and observed daily WT during two consecutive water years (WY). By calibrating two site-specific parameters - lateral saturated hydraulic conductivities of soil profiles and vertical saturated hydraulic conductivity of the underlying limestone bedrock - good agreement between simulated and observed daily WT was obtained (Nash-Sutcliffe efficiency coefficient >0.65; coefficient of residual mass <1%) within the units during WY96-97 (May 1995-April 1997). The validation of the model during subsequent WY98-99 at both units also showed Nash-Sutcliffe efficiency >0.55 and coefficient of residual mass <3%. It indicated that OntoSim-Sugarcane is able to simulate daily fluctuations of WT within the farm units and estimate lateral drainage/sub-irrigation and deep seepage that significantly contribute to the water balance at farms in the EAA. Thus, it can be a promising management tool to provide farmers with accurate assessment of water movement in this agricultural area.

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    • "The sugarcane collocated sites were in the Everglades Agriculture Area (EAA) in south Florida which is one of the prime farming areas developed on Histosols (Armentano, 1980). To maintain the agricultural productivity, drainage systems that consist of farm canals, ditches, and pump stations have been used to manage the hydrology in EAA (Kwon et al., 2010). In an average year, the EAA receives more rainfall than it needs for agriculture so water is pumped to Lake Okeechobee to the north (Bottcher and Izuno, 1994). "
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    ABSTRACT: Historically, Florida soils stored the largest amount of soil organic carbon (SOC) among the conterminous U.S. states (2.26Pg). This region experienced rapid land use/land cover (LULC) shifts and climate change in the past decades. The effects of these changes on SOC sequestration are unknown. The objectives of this study were to 1) investigate the change in SOC stocks in Florida to determine if soils have acted as a net sink or net source for carbon (C) over the past four decades and 2) identify the concomitant effects of LULC, LULC change, and climate on the SOC change. A total of 1080 sites were sampled in the topsoil (0-20cm) between 2008 and 2009 representing the current SOC stocks, 194 of which were selected to collocate with historical sites (n=1251) from the Florida Soil Characterization Database (1965-1996) for direct comparison. Results show that SOC stocks significantly differed among LULC classes - sugarcane and wetland contained the highest SOC, followed by improved pasture, urban, mesic upland forest, rangeland, and pineland while crop, citrus and xeric upland forest remained the lowest. The surface 20cm soils acted as a net sink for C with the median SOC significantly increasing from 2.69 to 3.40kgm(-2) over the past decades. The SOC sequestration rate was LULC dependent and controlled by climate factors interacting with LULC. Higher temperature tended to accelerate SOC accumulation, while higher precipitation reduced the SOC sequestration rate. Land use/land cover change observed over the past four decades also favored the C sequestration in soils due to the increase in the C-rich wetland area by ~140% and decrease in the C-poor agricultural area by ~20%. Soils are likely to provide a substantial soil C sink considering the climate and LULC projections for this region.
    Full-text · Article · Jul 2014 · Science of The Total Environment
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    • "edu) or calculated by fi tting the data with van Genuchten's (1980) equation at two soil profi les of a farm. Two hydrologic parameters – lateral saturated hydraulic conductivities of soil profi les and vertical saturated hydraulic conductivity of the underlying limestone bedrock – were obtained from the calibration work previously conducted at the farm during WY 96–97 (Kwon et al., 2010 "
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    ABSTRACT: Water flow and P dynamics in a low-relief landscape manipulated by extensive canal and ditch drainage systems were modeled utilizing an ontology-based simulation model. In the model, soil water flux and processes between three soil inorganic P pools (labile, active, and stable) and organic P are represented as database objects. And user-defined relationships among objects are used to automatically generate computer code (Java) for running the simulation of discharge and P loads. Our objectives were to develop ontology-based descriptions of soil P dynamics within sugarcane- (Saccharum officinarum L.) grown farm basins of the Everglades Agricultural Area (EAA) and to calibrate and validate such processes with water quality monitoring data collected at one farm basin (1244 ha). In the calibration phase (water year [WY] 99-00), observed discharge totaled 11,114 m3 ha(-1) and dissolved P 0.23 kg P ha(-1); and in the validation phase (WY 02-03), discharge was 10,397 m3 ha(-1) and dissolved P 0.11 kg P ha(-). During WY 99-00 the root mean square error (RMSE) for monthly discharge was 188 m3 ha(-1) and for monthly dissolved P 0.0077 kg P ha(-1); whereas during WY 02-03 the RMSE for monthly discharge was 195 m3 ha(-1) and monthly dissolved P 0.0022 kg P ha(-1). These results were confirmed by Nash-Sutcliffe Coefficient of 0.69 (calibration) and 0.81 (validation) comparing measured and simulated P loads. The good model performance suggests that our model has promise to simulate P dynamics, which may be useful as a management tool to reduce P loads in other similar low-relief areas.
    Full-text · Article · Sep 2010 · Journal of Environmental Quality
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    ABSTRACT: A methodology and applications of ontology-based simulation are presented. An environment for building simulations based on the Lyra ontology management system is described which includes web-based visual design tools for constructing models and automatically generating simulation code. The ontology is used for representing all equations and all symbols appearing in these equations that are needed to describe a model. The example applications presented are models of soil, water, and nutrient management in citrus and sugarcane. Results thus far show that the ontology-based approach has advantages for representing the model structure, equations, and symbols, that complex models can be described in this format, and that efficient simulation code can be generated automatically from the ontology definition of the model. Potential applications, not yet fully explored, include ability to automatically connect models and data sources, using the ontology to organize model bases containing many models and model components, and using ontology reasoners to search for models, automatically discover model similarities and differences, and generate model instances from general principles.
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