Novel technologies for estimating crop water needs include mainly remote sensing evapotranspiration estimates and decision support systems (DSS) for irrigation scheduling. This work provides several examples of these approaches, that have been adjusted and modified over the years to provide a better representation of the soil–plant–atmosphere continuum and overcome their limitations. Dynamic crop simulation models synthetize in a formal way the relevant knowledge on the causal relationships between agroecosystem components. Among these, plant–water–soil relationships, water stress and its effects on crop growth and development. Crop models can be categorized into (i) water-driven and (ii) radiation-driven, depending on the main variable governing crop growth. Water stress is calculated starting from (i) soil water content or (ii) transpiration deficit. The stress affects relevant features of plant growth and development in a similar way in most models: leaf expansion is the most sensitive process and is usually not considered when planning irrigation, even though prolonged water stress during canopy development can consistently reduce light interception by leaves; stomatal closure reduces transpiration, directly affecting dry matter accumulation and therefore being of paramount importance for irrigation scheduling; senescence rate can also be increased by severe water stress. The mechanistic concepts of crop models can be used to improve existing simpler methods currently integrated in irrigation management DSS, provide continuous simulations of crop and water dynamics over time and set predictions of future plant–water interactions. Crop models can also be used as a platform for integrating information from various sources (e.g., with data assimilation) into process-based simulations.

中文翻译：

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动态作物模型和遥感灌溉决策支持系统：水胁迫概念的回顾，以改进对水的需求估算

估算作物需水量的新技术主要包括遥感蒸散量估算和灌溉计划决策支持系统（DSS）。这项工作提供了这些方法的几个示例，这些示例已经过几年的调整和修改，以更好地表示土壤－植物－大气的连续性并克服了它们的局限性。动态作物模拟模型以正式方式综合了有关农业生态系统各组成部分之间因果关系的相关知识。其中，植物与水，土壤之间的关系，水分胁迫及其对作物生长和发育的影响。根据控制作物生长的主要变量，可以将作物模型分为（i）水驱动和（ii）辐射驱动。从（i）土壤含水量或（ii）蒸腾不足开始计算水分胁迫。在大多数模型中，胁迫以类似的方式影响植物生长和发育的相关特征：叶片扩张是最敏感的过程，即使计划灌溉时通常不考虑叶片扩张，即使冠层发育过程中长时间的水分胁迫可以持续减少叶片对光的拦截；气孔关闭减少了蒸腾作用，直接影响干物质的积累，因此对于灌溉计划至关重要。严重的水分胁迫也可以增加衰老率。作物模型的机械概念可以用于改进目前集成在灌溉管理DSS中的现有更简单的方法，提供一段时间内作物和水动力学的连续模拟，并设定未来植物与水相互作用的预测。作物模型也可用作将来自各种来源（例如，数据同化）的信息集成到基于过程的模拟中的平台。