Ms Wollweber, you lead the Food + Farming group at Laser Zentrum Hannover (LZH). What is your team working on?
We are working on various concepts with lasers and optical appliances in the agriculture and food production sector. One of these concepts is to use a laser against any plant we might define as a weed.
How exactly does it work?
The image recognition technology we use can indentify different plants. It can differentiate between a cultivated crop and other plants which can harm the crop’s growth and reduce harvest yield. If a weed is detected, a laser beam of 5 mm diameter is activated, which for a tenth of a second focusses at the plant’s growth centre. The cells die off and the plant dries out.
How far along are you in the development process?
The idea has been around for a few decades. It was just the technology that needed to be developed further: The artificial intelligence of the camera and the compact laser. We use a laser system with an optical output of 100 watts, which until now we have used to treat single rows. To be able to treat several rows at a time, we want to work with laser manufacturers to develop more powerful systems.
We ask ourselves what kind of treatment makes the most sense, whether we should just concentrate on the area around the crop or also on the area between rows. Depending on the distance between the plants, one solution may be to supplement the treatment with other methods, for example with hoes. We may be able to combine various processes here. We expect the technology to be ready for use in two to three years.
What are the advantages?
With the help of the laser we are able get very close to the crop, even with sensitive crops. We are also able to treat every plant individually. These latest developments open an entire new world of possibilities because there is an increasing awareness of sustainability in agriculture. If we treat a weed with less energy, we inhibit growth until the plant sprouts again. This means weeds are no longer competing with crops and we can do more in terms of biodiversity. If I want a certain weed to not seed, the solution may be to simply stunt its growth, rather than destroy it.
Can the laser damage the soil?
Not at all. We only treat the plants; the laser energy is absorbed by their water. The earth components are heated to the same extent as they are by the sun.
When should you use the device in the field?
The growth stage plays an important role. In very small plants, detection is a challenge. The more leaves we can see, the easier the identification. But the weed should not become too large: Up to the four-leaf stage we can carry out the treatment very effectively, but when plants are larger, we need even more energy because they are getting more robust. Therefore, progress across the field is significantly slower. This, in turn, means that the process is less economical.
How will the laser move in the field
Naturally, you would think of the laser being pulled behind a tractor in classic fashion. But with robots, the laser would be able to move across fields independently. We are also considering combining the technology with a drone: With the data we can specify the distribution of weeds and use an intelligent treatment strategy to determine when and where treatment is needed.
How does the laser compare to chemical methods?
A multitude of factors such as the initial costs or the energy and working time need to be considered. Currently, the initial costs are still very speculative. What we do know, is that there is hardly any wear and tear and no consumables other than energy. In terms of energy input, if we include the production of the chemical agents, we work on a similar scale. Working time is, of course, influenced by the speeds of 2-4km/h and whether treating only one row versus multiple rows at the same time. In the future, however, we want to be able to treat up to four rows simultaneously. The prerequisite for this is, of course, that the laser can do this. We are still in the development phase. As soon as autonomy makes its way into the field, working time will no longer be such a big issue, as the device will be ready for use around the clock, no matter the weather.
What’s up next in the project?
Technologically, we now have everything we need to successfully start field testing. More specifically, in vegetable and grain production, which we intend to look at 2020. Now, it is above all about recognising the requirements of producers and gathering their experiences in order to create good, competitive products in the future.