Despite subtle variations in soil moisture (SM) across a paddock, irrigation scheduling in New Zealand dairy farms is solely based on the SM monitored at a single location, primarily using an Aquaflex soil moisture sensor at a specified root depth. This study aimed to address this issue by assessing the “effective” root depth of a pasture, calibrating the Aquaflex soil moisture sensor and evaluating the spatial and temporal variability of SM. Twenty non-weighing lysimeters and 1 Aquaflex with 2 sensors installed 125-m away from the lysimeters on the same paddock were utilized for the study. TDR probes with 200-, 500- and 900-mm lengths were installed vertically adjacent to the Aquaflex and the lysimeters for monitoring spatio-temporal variability in SM, and calibrating the Aquaflex. A dry down experiment was performed for investigating the root depth of the pasture. All TDR probes responded to wetting and drying events, with varying SM measurements both vertically and horizontally, due to variations in soil type at different locations, indicating a need of SM monitoring at different locations in the paddock for irrigation scheduling. There was a strong linear relationship between the Aquaflex and TDR probes readings, which can be used to calibrate the Aquflex and improve its reliability for measuring soil moisture and in turn irrigation needs. Over the dry down period, out of the total moisture change in the 0–900-mm soil profile, 96% was contributed by 0–500 mm, indicating that the significant root depth of the pasture lies on the top 500-mm soil profile. Findings of the study can contribute to better irrigation scheduling and to conserve water.

尽管整个围场的土壤湿度 (SM) 存在细微差异，但新西兰奶牛场的灌溉计划仅基于在单个位置监测的 SM，主要使用指定根深的 Aquaflex 土壤湿度传感器。本研究旨在通过评估牧场的“有效”根深、校准 Aquaflex 土壤湿度传感器以及评估 SM 的时空变异性来解决这个问题。研究使用了 20 台非称重式蒸渗仪和 1 个配备 2 个传感器的 Aquaflex，它们安装在距离同一个围场的蒸渗仪 125 米处。长度为 200、500 和 900 毫米的 TDR 探头垂直安装在 Aquaflex 和蒸渗仪附近，用于监测 SM 的时空变化并校准 Aquaflex。进行了干燥实验以研究牧场的根部深度。由于不同位置土壤类型的变化，所有 TDR 探头都响应润湿和干燥事件，垂直和水平方向的 SM 测量值不同，这表明需要在围场的不同位置进行 SM 监测以进行灌溉调度。Aquaflex 和 TDR 探头读数之间存在很强的线性关系，可用于校准 Aquflex 并提高其测量土壤湿度和灌溉需求的可靠性。在干旱期间，在 0-900 毫米土壤剖面的总水分变化中，96% 由 0-500 毫米贡献，表明牧场的显着根深位于 500 毫米土壤剖面的顶部.