Precision agriculture is an approach to farming that seeks to optimize crop health and productivity by ensuring that the right amounts of fertilizer and water are administered at all times. The benefits of precision agriculture are both economic as well as environmental.
The approach relies on a large range of sensors that detect various characteristics of the crop and soil. Based on these measurements, decisions can be made about the optimum amount of water, fertilizers, and pesticides to apply.
Some of the precision agriculture sensors rely on multi-spectral optical (light) measurements and below you can read more about this particular type of sensor.
What are multi-spectral sensors?
A multi-spectral sensor detects the spectral content of the light that is either reflected off or transmitted through a sample material. In our case, the sample can be the leaves of the plants as an example. The multi-spectral sensor will measure how much of each wavelength of the light is reflected or absorbed. And based on these measurements characteristics of the sample can be determined.
Why use multi-spectral sensors?
The key benefits of multi-spectral sensors are:
- It is a non-destructive measurement
- It can be done from a distance without touching the sample
- It is fast – often real-time – and can give immediate results
- It does not require any maintenance costs once the instrument is purchased
Different types of multi-spectral sensors
Agriculture sensors based on spectral measurements generally come in two forms:
- Handheld units that you can carry around and use to measure directly at the plants at a short distance
- Drone-mounted units that are used to fly over the plants and measure at a distance of several meters
For obvious reasons these sensors for both type of units, needs to be compact, low weight, environmentally stable and consume low levels of power. Spectral sensors used to be large benchtop instruments, but recently, ultra-compact sensors have been developed that is very well suited for agriculture sensors.
One common example of an application of multi-spectral sensors is the monitoring of plant health. The Chlorophyll in the plants contains Nitrogen and by monitoring the Chlorophyll it is possible to determine whether the plant is getting enough fertilizer (Nitrogen), too little, or too much. Chlorophyll absorbs light at blue and red wavelengths and these absorption levels can be used to determine the plant’s condition. Chlorophyll also exhibits fluorescence in the red wavelength range and you can see an example of a measurement done with our ultra-compact PEBBLE VIS spectrometer here.