CPM - Cotton Production Model

A new process-based cotton model, CPM, has been developed to simulate the growth and development of upland cotton (Gossypium hirsutum L.) throughout the growing season with minimal data input. CPM predicts final cotton yield for any combination of soil, weather, cultivar and sequence of management actions. Over the last 30 years, the U.S. Department of Agriculture's (USDA) Agricultural Research Service (ARS) has conducted a wide range of research on cotton, including work to develop a series of "production models" designed to serve as decision aids to cotton producers. In 1996, ARS decided to develop a new "second generation" Cotton Production Model (CPM) that would retain the best features of the earlier versions in a new, more versatile, and more user friendly framework. The development process was completed to the stage of beta-testing, when the need to redirect limited resources to other priorities caused ARS to decide not to complete the validation process. ARS believes that CPM, while only partially validated, has the potential to make useful contributions to American cotton producers when completed. For these reasons, ARS decided to make the model available for further development and commercialization. The Cotton Production Model (CPM) was developed with a modular structure using an object-oriented programming language, C++. The model draws upon the latest scientific knowledge available, and is intended to be used with a wide variety of cotton types across the entire US Cotton Belt. CPM is written in C++ using a new modular structure that allows flexibility and adaptability. This object-oriented structure should allow modules to be incorporated into process-based models of other crop species (see Acock, B. and V. R. Reddy. 1977. Designing an object-oriented structure for crop models. Ecological Modeling 94: 33-44). In addition to being modular and generic, CPM has other advantages over earlier models. Compared to previous cotton models, CPM is more robust, more user-friendly, more easily maintained, and more easily updated with future advances in science. The algorithms that simulate crop growth are derived in part from the best of each of the previous models, and they incorporate new physiological information as well. A new feature of CPM is that it incorporates 2DSOIL, an excellent up-to-date soil and root process model (see Timlin, D. J., Y. Pachepsky, and B. Acock. 1996. A design for a modular, generic soil simulator to interface with plant models. Agronomy Journal 88:162-169 ). 2DSOIL tracks water movement through the soil-plant-atmosphere continuum with hourly time-steps. It also incorporates a new model of plant water relations that responds realistically to water stress. CPM has updated treatments of carbon and nitrogen stresses compared to previous models, and it is designed for easy addition of responses to phosphorus and potassium. Because the growth of each leaf, inter-node and fruit is simulated separately, CPM should be easily linked to pest or disease models. CPM has the potential to be useful as a decision aid for cotton farmers and crop production consultants. If fully developed, it would be a valuable tool to optimize management inputs such as irrigation, fertilization, plant growth regulators, and defoliant application prior to harvest. In its current version, however, CPM has not yet been fully validated to be useful as a decision aid. The released version of CPM should be considered an advanced model suitable for research purposes. ARS does not endorse its use for any other purpose at this time. Of particular importance to a decision aid model is the user interface. The interface under which CPM has been developed and tested is one that was earlier developed for the soybean model, GLYCIM, and has been documented elsewhere (Acock, B., Pachepsky, Y. A., Mironenko, E. V., Whisler, F. D., and Reddy, V. R. 1999. GUICS: A Generic User Interface for On-Farm Crop Simulations. Agronomy Journal. 91:657-665). CPM is part of the current release of GUICS.本研究开发了一款全新的基于过程的棉花模型：棉花生产模型（Cotton Production Model, CPM），可在仅需少量输入数据的前提下，模拟陆地棉（Gossypium hirsutum L.）整个生育期的生长发育过程。该模型可针对土壤、气象、品种以及管理措施组合的任意情况，预测棉花最终产量。 过去30年间，美国农业部（U.S. Department of Agriculture, USDA）下属的农业研究局（Agricultural Research Service, ARS）开展了大量棉花相关研究，包括开发一系列旨在为棉花种植者提供决策辅助的“生产模型”。1996年，ARS决定开发全新的“第二代”棉花生产模型（Cotton Production Model, CPM），旨在在全新、更通用且更友好的框架中保留早期版本的核心优势。该模型的开发已推进至β测试阶段，后因需要将有限资源重新分配至其他优先事项，ARS决定不再完成验证流程。 ARS认为，尽管该模型仅完成了部分验证，但若开发完成，其有望为美国棉花种植者提供切实助力。基于此，ARS决定将该模型开放，以供后续开发与商业化应用。 本棉花生产模型（CPM）采用面向对象编程语言C++开发，具备模块化架构。该模型整合了当前可获取的最新科学知识，适用于美国棉花带范围内的多种棉花类型。CPM基于全新模块化架构编写，具备出色的灵活性与适配性。这种面向对象的架构支持将模块集成至其他作物的基于过程的模型中（详见Acock与Reddy，1977年：《为作物模型设计面向对象架构》，《生态建模》第94卷：33-44页）。除模块化与通用性外，CPM相较于早期模型还具备多项其他优势：与以往棉花模型相比，CPM的鲁棒性更强、用户界面更友好、更易于维护，也更便于随着后续科学进展进行更新。其模拟作物生长的算法部分整合了各早期模型的最优方案，同时融入了全新的生理学研究成果。CPM的一项新特性是集成了2DSOIL——一款优秀的现代化土壤与根系过程模型（详见Timlin等，1996年：《适配植物模型的模块化通用土壤模拟器设计》，《农学杂志》第88卷：162-169页）。2DSOIL以小时为时间步长追踪土壤-植物-大气连续体中的水分运移过程，同时集成了可真实响应水分胁迫的植物水分关系新模型。相较于早期模型，CPM更新了碳、氮胁迫的处理逻辑，且预留了便捷添加磷、钾胁迫响应的接口。由于该模型可分别模拟每一片叶片、每个节间与每个棉果的生长过程，因此可轻松与病虫害模型进行对接。 CPM有望成为棉农与作物生产顾问的决策辅助工具。若完成全部开发工作，它将成为优化灌溉、施肥、植物生长调节剂施用以及收获前脱叶剂喷施等管理投入的实用工具。但就当前版本而言，CPM尚未完成全部验证流程，尚不具备作为决策辅助工具的实用性。目前发布的CPM版本仅适用于科研用途的高级模型，ARS现阶段不认可其用于其他任何用途。对于决策辅助模型而言，用户界面尤为关键。CPM开发与测试所使用的界面源自此前为大豆模型GLYCIM开发的通用界面，相关细节已在其他文献中记载（详见Acock等，1999年：《GUICS：农田作物模拟通用用户界面》，《农学杂志》第91卷：657-665页）。CPM是GUICS当前发布版本的组成部分。