Willemijn Appels
Dr Willemijn Appels


Precision agriculture and irrigation start with careful observation of each agricultural field during the growing season with a variety of sensors below, on, and far above the ground. Data obtained by sensors needs to be analyzed and translated into a management decision that is optimized to the crop being grown, the irrigation equipment being used, and the management style of the producer. We use existing and new sensors to obtain a suite of observations to get a better, timely and quantitative picture of soil water availability and crop water demand during the growing season. 

Examples of our tools are: soil moisture sensors, weather stations, portable probes, thermal infrared cameras, a UAV (drone), remote sensing imagery.

In addition to hands-on experimenting, we develop plant-soil-water models to simulate the effects of new irrigation techniques and adaptive scheduling on yield of the crops found in southern Alberta. The use of computer models allows an analysis of these effects over the entire range of soil types and topographic features found in the region. Findings from the lab and field experiments are used to calibrate the models. The results of the computer simulations and the map visualizations thereof help guide field experimental programs. They are also input to financial calculations to evaluate return on investment of variable rate irrigation systems.


Areas of expertise

  • unsaturated zone hydrology
  • irrigated agriculture


Current research projects

  • Below The Surface: Using Soil Moisture Observations And Simulations To Optimize Installation And Operation Of Subsurface Drip Irrigation Systems 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.  Learn more about this NSERC-funded project.


  • Sensor-based scheduling of irrigation applications for potatoes under a VRI pivot
    MSc project of Danielle Crawford (LC grad) under supervision of Dr. Willemijn Appels and Dr. Kenny Corscadden. The goal of the project is to quantify and explain the variability of plant available water in various management zones of a potato field. Funded by an NSERC Discovery grant (Dr. Kenny CorscaddenDalhousie University) and the Mueller Applied Research Chair with in-kind support by Alberta Agriculture and Forestry.


  • Evaluating the impact of landscape variability on plant water demand and irrigation scheduling
    Field project near Coalhurst AB, where we apply a multi-method approach to measure the variability of water availability and water demand in a field and translate this into an irrigation management decision. MSc project of visiting student Jessica Snoek (Wageningen UR, the Netherlands). Funded by the Mueller Applied Research Chair with in-kind support from Chinook Crop Care and Double H Feeders.


  • We participate in a study of the use of microwave sensors to measure soil moisture availability in fields. This study is led by AAFC (Evan Derdall, Saskatoon).


Publications and presentations


A complete listing of Willemijn’s publications can be found on Google Scholar.