Students in Science

Utah State student Glen Ritchie and former student Dennis Wright are helping make farming easier and more precise with the use of a tool that is, if not light-years, at least several wavelengths ahead of most conventional farm equipment.


The device uses a portable spectrometer (worn like a backpack with a few attachments) to measure wavelengths of light reflected by plants and determining whether they are nitrogen or water stressed before they exhibit visible signs of trouble. Spectrometers measure wavelengths of light, including many we cannot see with the unaided eye. A plant getting too little nitrogen or water eventually looks different from a healthy plant, but its health and productivity suffer long before it shows outward signs of stress.

The research focused on gathering data to ground-truth data gathered using satellite images and NASA aerial, infrared photographs-methods that allow growers to closely monitor the condition of crops in every part of a vast field.

Wright says the project was very important in helping him learn more about plants, understanding what they need in order to thrive, and enriched his education by giving him an opportunity to be part of a research team.

"I learned how to collect and analyze data, how to write reports for different audiences (farmers, researchers, and the general public), and how projects for NASA work," he said.

The project also allowed him to talk with farmers and to put himself in their shoes. He was motivated by the idea that research he did might be valuable to farmers and help them produce the food on which we all rely.

A chlorophyll meter was used to test winter wheat plants and satellite images tested the same plots. The team found that satellite images and the chlorophyll meter were both accurate in detecting levels of nitrogen stress.

The satellite images predicted yield with better accuracy than did the chlorophyll meter, but cost is a drawback. Overall, the satellite can test a larger area than the chlorophyll meter, but the meter can test individual plants and provide quantified amounts of nitrogen deficiency. As a result of his project, Wright was offered a job at Utah State as the program coordinator with the university's NASA Research Center.

Ritchie focused on using the spectrometer to detect stress levels in plants, providing more information to farmers and preparing them to change the ways they look at crops.

His studies were aimed at determining the spectral differences between nitrogen-stressed, water-stressed, and healthy winter wheat. Nitrogen-stressed plants develop a particular color, more yellow than its healthy counterparts. A water-stressed plant may remain green, but has stunted growth. The spectrometer measures the color of the plants, and-based on what is reflected-farmers can determine what corrective action to take before yields and profits suffer. Spectrometers also provide data to ground-truth satellite or aerial images of large fields that help growers see everything "up close" from a vantage point high overhead.

"The work on reflectance measurements has expanded my knowledge base by forcing me to learn a little bit more about subjects that I would not have otherwise explored, such as electronics, computer trouble-shooting, and experiment design," Ritchie said. "And it's exciting to try to craft my research toward the needs of farmers and other end-users."

Perhaps the biggest boost to his academic career has been learning how to take a subject that he knows little about, research it, troubleshoot it, and finally feel like he can use it correctly and effectively to obtain useful and repeatable results. He credits the project with helping him increase his creativity and his understanding of how the equipment works. It also makes him feel more confident knowing that he can bring these acquired skills with him as he searches for employment after graduate school.

Story by Nathan Plott
Reprinted from "Utah Science," a publication of the Utah Agricultural Experiment Station at Utah State University