Below the surface: using soil moisture observations and simulations to optimize installation and operation of subsurface drip irrigation systems in southern Alberta

地下滴灌（SDI）是一种非常节水的灌溉技术，它以非常低的速度将水输送到植物可以吸收的根区。SDI系统可用于不规则形状的田地，可以完全自动化，并可以提供养分和水，这为在不增加用水量的情况下增加作物产量创造了机会。SDI系统的这些方面正在推动阿尔伯塔南部对SDI技术日益增长的兴趣。莱斯布里奇学院和南方灌溉公司正在合作一个项目，探讨地下滴灌系统在水和养分利用效率方面的管理。 ** 该项目结合了实验室，现场和计算机实验。在广泛的实验室实验中，我们将建造三个木制箱子与常见的南部阿尔伯塔土壤和种子苜蓿作为测试作物。在每个仓中，将在两个深度处安装两个具有不同发射器间距的SDI系统，每个仓总共安装四个系统。我们将使用超过40个土壤水分传感器，评估每个系统在各种灌溉管理计划下向作物供水的能力。在项目的第二阶段，我们还将评估SDI系统向作物输送磷肥的能力。在实验室实验中获得的见解将在2018年生长季节应用于真实的农田中SDI系统的灌溉管理。互补的计算机模拟将帮助我们探索在土壤和天气条件下灌溉水管理的假设情景，而不是在实验室和现场经历的情景。实验室的大型设置为在室内环境中测试用于大田作物的灌溉技术创造了独特的机会。正因为如此，我们可以在生长季节之外进行实验，并在不影响生产者产量和利润的情况下进行大范围的水管理计划。实验室，计算机模型和现场结果的整合将使我们能够将我们的研究结果推广到更好的SDI安装和管理策略，为加拿大西部的生产商。 **********

Subsurface drip irrigation (SDI) is an extremely water-efficient irrigation technology that delivers water at very low rates right into the root zone where plants can take it up. SDI systems can be used on irregularly shaped fields, can be fully automated, and can deliver nutrients as well as water, which creates an opportunity to increase crop yields without increasing water use. These aspects of SDI systems are fueling an increasing interest in SDI technology in southern Alberta. Lethbridge College and Southern Irrigation are partnering in a project that explores management of subsurface drip irrigation systems in terms of water and nutrient use efficiency. **The project combines laboratory, field, and computer experiments. In the extensive laboratory experiment, we will construct three wooden bins with common southern Alberta soils and seed alfalfa as a test crop. In each bin, two SDI systems with different emitter spacing will be installed at two depths for a total of four systems per bin. We will evaluate the ability of each system to deliver water to the crop under various irrigation management schedules with > 40 soil moisture sensors. In a second phase of the project, we will also evaluate the ability of the SDI systems to deliver P fertilizer to the crops. The insights gained in the laboratory experiments will be applied in the irrigation management of SDI systems in real fields during the growing season of 2018. Complementary computer simulations will help us explore what-if scenarios of irrigation water management in soils and weather conditions other than those experienced in the lab and field. The large setup in the laboratory creates a unique opportunity to test an irrigation technology destined for field crops in an indoor setting. Because of this, we can run experiments outside of the growing season and experiment with a large range of water management schedules without compromising a producer's yield and profit. The integration of the laboratory, computer model, and field results will allow us to generalize our findings into better SDI installation and management strategies for producers in western Canada. **********