基于变量灌溉动态分区管理的冬小麦产量与节水效果

    Yield and water-saving effects of winter wheat based on variable rate irrigation dynamic zoning management

    • 摘要: 喷灌机机载式红外温度传感器系统是动态监测农田作物水分亏缺状况、构建变量灌溉(variable rate irrigation, VRI)决策支持系统的重要工具。为了评估圆形喷灌机机载式红外温度传感器系统在变量灌溉动态分区管理中的应用效果,该研究以气象参数和土壤水分传感器网络构建的均一灌溉(uniform rate irrigation, URI)决策方法为对照,评估了基于气象参数、土壤水分传感器网络和作物冠层温度的变量灌溉决策方法对华北平原冬小麦灌溉制度、土壤含水率空间分布均匀性和节水增产效果的影响。在河北省邢台市大曹庄中国水利水电科学研究院智慧灌溉技术与装备创新示范推广基地开展试验,试验区为三跨加悬臂圆形喷灌机控制灌溉面积7.07 hm2,2021年试验区等分为2个子区,布置URI和VRI处理,2022年试验区等分为4个子区,布置URI处理、基于等间隔法进行管理区聚类划分的VRI(T1)处理、基于“Jenks”自然断点法进行管理区聚类划分的VRI(T2)处理和基于几何间隔断点法进行管理区聚类划分的VRI(T3)处理。结果表明,在冬小麦生育期内,URI和VRI处理灌水7~10次,2 a平均灌水量分别为201和173 mm。开展VRI管理后,冬小麦主根区的土壤含水率空间分布均匀性和产量均匀性提高。2021年URI和VRI处理的冬小麦产量分别为9 470和9 574 kg/hm2,2022年的冬小麦产量较2021年分别降低6.7%和6.0%。变量灌溉处理的管理区聚类划分方法未对灌溉制度和产量产生显著影响。与URI处理相比,VRI处理能够减少灌溉水量,且对产量和水分利用效率无显著影响。研究结果可为基于喷灌机机载式红外温度传感器系统的变量灌溉动态分区管理方法的建立提供指导,为变量灌溉决策支持系统的开发升级提供技术支持。

       

      Abstract: Infrared thermometers (IRTs) is one of the most important tools that mounted on the moving sprinkler irrigation. The water stress of crop can be dynamically monitored to construct the decision-making on the variable rate irrigation (VRI) of center pivot irrigation. This study aims to evaluate the application performance of IRTs in dynamic zoning management. The prescription maps were also constructed using IRTs. A systematic investigation was implemented to explore the influences of VRI decision with meteorological parameters, soil moisture sensor network and canopy temperature on irrigation scheduling, soil water content distribution, water saving and wheat yield. A comparison was then made with the uniform rate irrigation (URI) decision with the meteorological parameters and soil moisture sensor network. The experiment was carried out at the intelligent irrigation and equipment innovation demonstration and promotion base of China Institute of Water Resources and Hydropower Research, Dacaozhuang, Xingtai, Hebei Province of the North China Plain in 2021 and 2022. The two years were both dry years. The experimental area was 7.07 hm2 that controlled by a three-span center pivot VRI system with an overhang. Variable-rate water was applied along the lateral and travel direction. The control was realized via the duty cycle of a solenoid valve ahead of each sprinkler and the travel speed of the center pivot. In 2021, the experimental site was divided into two subzones for the URI and VRI treatments. In 2022, the management zones were defined in the treatments of URI, and VRI (T1) with the equal interval , VRI(T2) with the “Jenks” natural break classification, and VRI (T3) with the geometric interval breakpoint, respectively. As such, four subzones were allocated with the equal area. The results indicated that the irrigation times were 7 to 10 in both URI and VRI treatments during the winter wheat growing season in a dry year. Specifically, the average application amount was 201 and 173 mm, respectively, which was greater than the traditional management with 3 to 5 irrigation events of 232 mm application amount. After the dynamic VRI management, the spatial distribution was uniform in the soil water content in the majority of the root zone, leading to the high yield of winter wheat. The wheat yields were 9 470 and 9 574 kg/hm2 in URI and VRI treatments in 2021, respectively. The yield and water use efficiency of winter wheat were not significantly decreased (P>0.05). However, the irrigation amount was decreased by 13% and 25% in 2021 and 2022, respectively. The findings can provide the guidance to establish the dynamic zoning management of variable irrigation using IRTs mounted on moving sprinkler irrigation system. A technical support can also be offered to develop and upgrade the decision support system of variable irrigation

       

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