The robot buggies roll through fields on upright pillars, so they can coast over plants without disturbing them.
The goal is to collect data about how crops grow.
Called Project Mineral, it is part of Alphabet's X company, which aims to create world-changing technology from radical "moonshot" ideas.
The team says its main goal is to address the world's increasing need for food and the sustainability of growing it.
While farmers may have information about the soil content or the weather, the buggy robot was designed to see how plants were "actually growing and responding to their environment", the company said.
The buggy can also record information such as plant height, leaf area and fruit size.
And all that data is plugged into a machine-learning system to try to spot patterns and insights useful to farmers.