The fluorescence technology or rather methodology itself is actually pretty simple and straightforward. A light source (the WEED-IT sensor) emits light from the spray boom towards the soil and plants. The biggest part of the light is absorbed by the plant and used for photosynthesis. The living chlorophyll emits a small portion of near infra-red (NIR) light as a reaction which is called ‘chlorophyll fluorescence’. WEED-IT measures this wavelength emitted from the living chlorophyll and so distinguishes a living plant from dead plant matter, soil and any other substances. Besides, the more chlorophyll a detected plant contains, the more near infra-red light it will emit which relates to the size and number of the detected leaves and plants.
In everyday life, fluorescence technology is used to make license plates, road signs and worker gear more visible at night and the same goes for a blacklight that makes your teeth look green.
At the speed of light!
One of the reasons why the WEED-IT fluorescence technology is so fast, is because it uses the speed of light to detect chlorophyll in plants. This means that any (type of) weed, no matter how small, is always detected at any speed. A second distinguishing reason, is that WEED-IT technology does not require nor involve any image processing: weeds nor plants aren’t classified like (RBG) camera systems do. A third reason for WEED-IT being ultrafast, is that both the weed detection and elimination are done by the same system: WEED-IT sensors followed by WEED-IT 100 Hz pulse width modulation (PWM) nozzles.
All this make it possible that the WEED-IT sensors are capable of detecting weeds as small as 1 cm2 at a speed of up to 25 km/h. Speaking of fast, the WEED-IT technology is also used on trains to spray railway tracks with speeds up to 50 km/h!
What makes fluorescence technology foolproof?
Fluorescence technology is foolproof in detecting weeds because it is triggered by the amount of chlorophyll in weeds. WEED-IT uses clever and compact algorithms to distinguish between an actual plant or soil with just a fraction of fluorescence response. This means that anything containing chlorophyll, no matter how small or how large, is detected by the WEED-IT sensors with a success rate of up to 99%. It also means that the accuracy nor reliability are affected by shade, moisture nor daylight or darkness.
There is also a near infra-red signal coming from other objects in the background then just from the chlorophyll in the plants, which may lead to a signal to the WEED-IT sensor. To overcome this, the background noise is automatically filtered out in a clever way so it won’t generate a false fire.
Determining plant sizes
The WEED-IT fluorescence technology is also capable of determining the size of weeds and plants because the signal level relates to the number, as well as the size of the detected plants. This capability is the secret behind the unique WEED-IT dual spray mode that allows you to apply a low application rate (like 30 l/ha) full width and a higher rate (like 100 l/ha) on every single, bigger sized, weed detected. WEED-IT is the only system capable of offering this dual spraying technology, combing the detection and PWM technology into just one spray line!
Dual spray mode is ideal if your work window is tight and if you want to combat every single (volunteer) weed in just one pass. With just one type of spraying mixture in your tank, you can spot spray single weeds and, at the same time, eliminate volunteer weeds and crop residues from root crops effectively.
Timing is key
Successful weed management is all about timely weed management. The ideal weed elimination moment(s) depend on climate and weather, of course, but also on the type of crop harvested and the following crop. In hot climates/circumstances like in Australia, summer weed management is ideal to combat weeds effectively. In more moderate conditions, post-harvest and pre drilling are the best moments to combat (volunteer) weeds. With the right WEED-IT weed management and its high success rate, weeds can be tackled in the best possible way.