Two German engineers have found a scientific solution to a unique agricultural challenge: using ground-penetrating radar (GPR) for asparagus farming. All asparagus is tricky to harvest, because it grows quickly and must be cut at precisely the right height. If farmers cut it too low, it can damage the crop’s roots; too high, and it will lead to a reduced crop yield. White asparagus, considered a delicacy in Europe, is particularly difficult to cut at the right length, because it must be grown underground, covered by a black tarp so that no sunlight can hit the plant and turn it green.
So, to find the elusive crops, Jörg Schöbel and Daniel Seyfried, from the Department of High-Frequency Technology at Technische Universität Braunschweig in Germany, attached a GPR system to a cart to make a perfect asparagus detector. While it’s a relatively new technology for agriculture, GPR is already being used in several other industries. Archaeologists use it to survey sites, geologists use it to study groundwater systems and locate buried pipes, and militaries use it to detect hidden improvised explosive devices or tunnels.
GPR works by sending high-frequency radio waves into the ground. As the waves bounce back, a receiving antenna records the variations in return signals. A computer then measures the time it took the pulse to bounce back, and processes the data to form a map that shows exact location and size of whatever is hidden underground. It makes sense, then, for farmers to point a GPR detector at a mound of buried asparagus to find the perfect cutting height.
The researchers described their high-tech asparagus detector in the Journal of Applied Geophysics.
In this paper we present a new approach which utilizes ground penetrating radar for non-invasive sensing in order to obtain information on the optimal height for cutting the soil. Hence, asparagus spears of maximal length can be obtained, while keeping the roots at the same time undamaged. We describe our radar system as well as the subsequent digital signal processing steps utilized for extracting the information required from the recorded radar data, which then can be fed into some harvesting unit for setting up the optimal cutting height.
Eventually, they would like to see a GPR system attached to a harvester so that a machine could automatically trim asparagus spears when they reach the ideal height.
