In most of the cases the study of plants focuses on the part that sticks out of the ground. The subterranean parts – the roots – are often being neglected, despite being immensely important to the growth of the plants. The company Umweltanalytische Produkte GmbH (UP) and the association Centrum für Energietechnologie e.V. (CEBra) in Cottbus have therefore developed and successfully tested a new technology, which makes it possible to observe the growth of roots with great precision and in a gentle way. The Ministry for Economic and European Affairs of the State of Brandenburg supported this project.
“The root is an important but, unfortunately, often underestimated plant organ. It is in charge of absorbing water and nutrients,” Gerhard Kast, Manager of the company UP GmbH, and Maik Veste, responsible Project Manager at CEBra, pointed out in unison. Factors such as the concentration of nutrients and the water balance within the root system have a decisive impact on the growth of trees and plants, which, in turn, impacts the production of biomass.
This biomass is indispensable, especially for the restoration of land in regions where opencast mining is carried out – as is the case of Lusatia, an energy-producing region. In order to optimise the development of roots, it is of vital importance to study them directly, but until now this was almost impossible without seriously disturbing the soil and the plant itself.
Based on a concept created by CEBra, the company UP GmbH initiated application trials for which it received financial support through the “Grand Innovation Voucher” (“Großer Innovationsgutschein”) of the State of Brandenburg. The goal was to study the condition and development of plant roots without, as far as possible, seriously disturbing the surrounding soil. The two project partners that have known each other for years from previous joint projects could rely on Veste’s experience in the field of minirhizotron systems.
The minirhizotron technique is a non-destructive procedure, which formed the basis for the studies. Its advantage: observations of the roots without disturbing them. To this end, glass tubes are submerged in the soil. Information about the growth, lifespan and function of roots can be acquired through an only slightly invasive process. The growth of fungi (mycorrhiza) can also be observed well.
However, both project partners were dissatisfied with the current state of the technology and so they developed a computer-controlled movable camera in the framework of their project. The camera made it possible, for the first time ever, to create a fully automated depiction of the root system.
The system can be equipped with a CCD colour camera or a black and white camera. They depict the different root sections along the glass tube, which is submerged in the soil and up to 1.6 metres long. Special software is used to operate the two stepper motors, which can move in a circular and linear direction and allow for a precise positioning of the camera in the tube. This helps to observe the roots and record possible changes over a longer period of time.
Kast and Veste are especially proud of the repeatable exact positioning of the camera and the improved image quality. New image-processing software automatically combines the individual pictures in order to create an overall image of the whole root system along the entire tube. In the future the duo would like to add optimised and autonomous image recognition and root identification to the system.
Another impressive feature of the camera is its compact form: the diameter of the camera was reduced to only 28 mm. Disturbances to the soil and to root growth can thereby be avoided almost completely.
UP boss Kast wants to use this improved measuring system to conquer new business areas. “We are offering our clients precise information on whether certain land is suitable for energy crops, e.g. for the production of biogas or pellets,” he said. The technology could also be very valuable for the restoration of land in regions where opencast mining has been carried out.