Farmers have monitored the health and durability of their crops for millennia simply by walking among their rows of plants, observing changes over time and noting which varieties do best. Kansas State University (KSU) agronomists have now made that labor-intensive process quicker and more precise with the development of the Phenocart.

A collection of sensors attached to a repurposed bicycle wheel with handles that a breeder can easily push among plants in a field, the Phenocart rapidly collects data as it is pushed among the plots. It measures plant health vital signs like growth rate and color in the same way a Fitbit monitors human health signals such as blood pressure and physical activity.

International Maize and Wheat Improvement Center scientist Uttam Kumar operates the Phenocart at the Borlaug Institute for South Asia, in Laddowal, India. Image credit: Jared Crain. In a field experiment with thousands of plots, the Phenocart is a quick and portable way to evaluate plant health, its developers say. It can also help plant breeders design larger experiments.

“Larger sample size gives you more power,” says Jesse Poland, assistant professor in the departments of Plant Pathology and Agronomy at KSU. “Measuring phenotypes is very labor intensive and really limits how big of an experiment we can do.”

Scientists can outfit the Phenocart with different sensors depending on what they want to measure. Poland and his colleagues use one such sensor to measure how “green” their plants are.

“The measure of vegetation index or ‘greenness’ is really the easiest and [most] straightforward way to measure the overall health status of the plant,” says Poland.

The team also uses a thermometer to check leaf temperature—a good predication for crop yield. A global positioning system pinpoints exactly where the Phenocart has measured, helping the team organize their data, which is processed by software included in the Phenocart package.