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)是一种非常高效的灌溉技术，它以非常低的速率将水直接输送到植物可以吸收的根区。SDI系统可以在形状不规则的田地上使用，可以完全自动化，并且可以输送养分和水，这创造了在不增加用水量的情况下提高作物产量的机会。SDI系统的这些方面正在推动艾伯塔省南部对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，从水和养分利用效率的角度探索地下滴灌系统的管理。**该项目结合了实验室、野外和计算机实验。在广泛的实验室实验中，我们将建造三个木箱，以阿尔伯塔省南部常见的土壤和种子紫花苜蓿作为试验作物。在每个储存箱中，将在两个深度安装两个不同滴头间距的SDI系统，每个储存箱总共安装四个系统。我们将使用&gt；40土壤湿度传感器评估每个系统在不同灌溉管理计划下向作物输送水分的能力。在该项目的第二阶段，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年生长季应用于实地调查的SDI系统的灌溉管理。互补的计算机模拟将帮助我们探索土壤和天气条件下灌溉用水管理的假设情景，而不是实验室和田间经历的情况。实验室中的大型设置创造了一个独特的机会，可以在室内环境中测试一种用于大田作物的灌溉技术。正因为如此，我们可以在生长季节之外进行试验，在不影响生产商产量和利润的情况下，试验大范围的水管理时间表。实验室、计算机模型和现场结果的整合将使我们能够总结我们的发现，为加拿大西部的生产商制定更好的SDI安装和管理策略。**********

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. **********