Thermal imagery to precision ag: understanding crop water needs

Post by Jenny Seifert

Thermal imagery is among the many different ways WSC scientists are collecting data on water-related ecosystem services in the Yahara Watershed. Graduate student Sam Zipper, who is studying interactions between crops and groundwater, is using thermal imagery to hone our understanding of the water needs of crops, which could in turn improve crop production, especially under climate change and urbanization.

To take the thermal images, Sam got to fly over the watershed in a tiny plane.

This is what his field site looks like from the air.

This is what his field site looks like through a thermal infrared imaging camera.

The thermal infrared imaging camera measures the temperature of the land’s surface. Sam plugged this data, along with meteorological data and satellite-based measurements of the crop canopy’s height and fullness, into an advanced computer model that he developed, called High Resolution Mapping of EvapoTranspiration (HRMET). The model then gave him this image.

This image shows the varying rates of evapotranspiration, or the sum of the amount of water both the land and plants “sweat” into the atmosphere, across the crop field. By understanding evapotranspiration, we can understand how efficiently crops are using water and, thereby, understand which areas of the field are most sensitive to drought or water stress. The areas in red are the most water-stress sensitive spots in the field and would be the areas most in need of irrigation if a drought were to occur. What exactly is causing the water stress sensitivity is the next question Sam is trying to answer.

The HRMET model provides a more holistic understanding of what is happening in a crop field. Ultimately, it could improve ways farmers plan for and respond to dry spells and wet spells caused by both year-to-year weather variability and climate change.

Moreover, the data produced by HRMET could inform precision agriculture, an emerging approach that uses advanced data and technology to micromanage crops according to the many variables that affect their yields. Precision agriculture could help Yahara farmers maximize the amount of crops their land produces, which would be important for maintaining a strong rural economy as the watershed’s urban areas expand and farmland (potentially) shrinks.

Sam recently published a paper that presents the HRMET model.

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