Study On Crop Model Resource And Integrated Model Construction Key Technique

The crop system simulation is one of the key technologies in agricultural information studies. With the expansion of crop model research, new requirements about the method, efficiency, quality and tools for crop model construction were proposed. For developing agronomist-oriented intelligent modeling tools and promoting the innovation and development of crop system simulation, it is useful to adopt the technologies of modern artificial intelligence and software development and explore the new methodology of organization, stoage, sharing, integration, and management for crop models. The purpose of this study was to adopt the multidisciplinary theories and technologies for studying crop growth system, analyze and synthesize the modeling process, model structure, basic algorithm, parameter type and simulation data for crop growth model on the basis of the concept of crop model resources and integrated model construction, establish the key technology of organization, integration, sharing and management for crop model resources, and construct the Crop Model Resources Warehouse (CMRW) and resource-based Integrated Crop Modeling Construction System (ICMCS), which would lay a foundation for realizing intelligent and automated crop system simulation.Bringing the idea of resource-based integrated manufacturing into the field of crop modeling, the concepts, features and contents for Crop Model Resource (CRM), CMRW and Integrated CMR Construction (ICMRC) were developed. The crop model resources are composed of crop modeling technology resources and software development resources, and have manageable, reproductive, reusable and migration characteristics. The crop system simulation is the dynamic transformation process in the spaces of different states, the integrated construction for CMR provides the technical support for CRM's formation, and promotes the automatic access, dynamic storage and transfer for modeling technology resources and model software development resources. Development of integrated crop modeling system with the features of resource integration, self-learning, self-adaptation and component design can help researchers to construct and accumulate the unified, shareable and reusable CMR in non-programming environment, reduce the difficulty of model construction and development, and improve the efficiency and quality of the models.Adopting the ontology-based method into the field of crop system simulation, following the main line of crop modeling, the growth models and simulation systems for wheat, rice and cotton crops were comprehensively analyzed, crops simulation and crop model ontology were established, and then Crop System Simulation Framework composed of inner and outer knowledge frameworks for crop modeling and crop model was constructed. Crop simulation model and simulation ontology are the basis of crop simulation ontology, outer knowledge framework for crop modeling can be formed with the system simulation activity ontology as the main line and crops, data, simulation and simulation tasks, and so on as mutual integration ontology. The models or sub-models inner knowledge framework of crop development, biomass production, organogenesis, partitioning and yield formation, water and nutrient balance and so on, can be constructed based on crop growth rules and simulation model components. The crop system simulation framework with a comprehensive knowledge expression promotes the sharing and reusing values of crop model, and thus the design of reusable integrated modeling software architecture.Based on the crop system simulation framework and combining with model representation and component method, the mapping mechanisms of CMR were proposed, the crop growth meta-model and metadata constructed, and the integrated model construction theory and technology established. The crop model can be mapped into the synthesis of concepts and/or trees, model algorithms and/or charts and realization forms for crop model, and the model resources can be expressed as the new entity of "framework + rules + algorithm + template + components". Based on the inner knowledge framework for crop models and sub-models, software patterns and comprehensive data, the crop growth meta-models and metadata were constructed. With the techniques of component framework, description script of model, reflective component assembly, dynamic knowledge integration and model extraction, the CMR integration mechanism can realize the comprehensive synthesis of model structure, model components, algorithm knowledge and model parameters. The crop modeling activity is then transformed to the learning and practicse activity performed together by crop growth meta-model and meta-data, modeling learning mechanism, simulation support tools, model custom component and model engine. The technology of CMR mapping and integrated construction has realized the reuse of crop modeling knowledge and components framework.With the technology of relation database, the crop models were mapped to E-R model, in which crop model structure was constructed by using virtual node method, and modeling knowledge was organized by the integration of knowledge page, knowledge group and algorithm unit, and the properties of model components were described by using faceted classification scheme. By coupling with basal database and solution database for crop models, the relation database model of CMRW was constructed, including model framework library, algorithm library, experiment database and solution database. With the model solution library as the main line, CMRW implements retrieval of model framework, algorithm and parameters by using retrieval algorithm with three layers for CMR. Then, on the integrated database platform, the CMRW for wheat was constructed, thus validating the feasibility of construction and retrieval. The CMRW can accumulate basic resources for integration and reuse of crop model componentsUnder the support of the CMR integrated construction technology and the CMRW, the resource-based ICMCS was successfully developed using .Net platform, language C# and Microsoft SQL Server database, and actually applied to the modeling practices with wheat and barley. ICMCS has the characteristics of hierarchy, components and intelligence, is composed of sub-model frameworks, models and templates for growth period, biomass production, organ production, yield formation, water and nutrient balance. Based on logical crop growth models and modeling service agencies, the functions such as model construction, simulation operation, model preservation and output, model analysis and evaluation, model resource search, and model dictionary and tools are realized. Application tests showed that the ICMCS has strong versatility, adaptability and scalability, and may replace the traditional crop model construction mode of code-based programming. Through using the means of learning, customization, design, configuration, assembly, assessment, expansion, and others, agronomists can intelligently construct, develop, accumulate and test the CMR and preliminary model without programming.