ORBITAL REMOTE SENSING FOR THE MANAGEMENT OF AREAS IRRIGATED WITH A CENTRAL PIVOT SYSTEM

ABSTRACT Irrigated agriculture is considered one of the most important techniques for agricultural production in the world, despite being the sector that uses water resources the most. Thus, technological advances have been constantly developed and applied in the sector as a way to improve water management and reduce its consumption, considering that some cultures are affected by economic costs and feasibilities of production, because the water cost has increased significantly in recent years. Remote sensing is a technology that has provided good results for estimating evapotranspiration (ETr) in producing areas, enabling more efficient irrigation management for low costs. This study aimed to answer the question about how the generation of irrigation management zones (IMZs) can be used to optimize water use and improve irrigation systems and which ETr models are better for it. Three ETr estimation models (Surface Energy Balance Algorithm for Land [SEBAL], Mapping Evapotranspiration at High Resolution and with Internalized Calibration [METRIC] and Simple Algorithm for Evapotranspiration Retrieving [SAFER]) were used to design IMZs in center pivot cultivated with cotton. The design of IMZs with ETr data proved to be a viable alternative, making it possible to improve water management in irrigated systems, reducing costs with viability irrigation for cotton and others cultures. The METRIC method displayed the greatest ease in obtaining the data used in the ETr estimation for generating the IMZs.

摘要：灌溉农业被视作全球农业生产中最为关键的技术手段之一，尽管其同时也是水资源消耗量最大的产业部门。鉴于部分作物的生产受到经济成本与生产可行性的双重制约，且近年来水资源成本显著攀升，相关领域持续研发并应用各类技术，以优化水资源管理并降低耗水量。遥感技术已在产区蒸散量（evapotranspiration, ETr）估算方面取得良好应用成果，可实现低成本的高效灌溉管理。本研究旨在解答两大核心问题：其一，灌溉管理分区（irrigation management zones, IMZs）的生成可如何用于优化水资源利用、完善灌溉系统；其二，何种ETr估算模型更适配此类应用场景。本研究选用3种ETr估算模型——地表能量平衡算法（Surface Energy Balance Algorithm for Land, SEBAL）、高分辨率内嵌校准蒸散制图算法（Mapping Evapotranspiration at High Resolution and with Internalized Calibration, METRIC）以及蒸散量反演简易算法（Simple Algorithm for Evapotranspiration Retrieving, SAFER）——针对采用中心支轴喷灌（center pivot）系统种植的棉花田生成灌溉管理分区。研究证实，基于ETr数据构建灌溉管理分区是切实可行的优化方案，可有效提升灌溉系统的水资源管理水平，降低棉花及其他作物的灌溉生产成本。其中，METRIC方法在获取ETr估算所需数据以生成灌溉管理分区时，展现出最优的操作便捷性。