Plant-assessing leaf-clip sensor could be a big help to farmers
If crop plants aren't receiving enough nutrients, they'll typically have lower-than-normal nitrogen levels. A portable new device could allow farmers to check those levels on the spot, so they can start addressing the problem as soon as possible.
Developed by a team from the Singapore-MIT Alliance for Research and Technology (SMART) – which is MIT's research enterprise in Singapore – the prototype gadget is in fact a compact Raman spectroscopic sensor.
Like its full-size counterparts, it works by shining monochromatic laser light onto a sample – in this case, a living leaf. The molecules in that material vibrate in response, scattering the light in a unique manner. Therefore, by analyzing that scattered light, it's possible to ascertain which chemicals are present in the sample.
When it comes to using such technology in agricultural applications, plant samples typically have to be taken from the field to a benchtop Raman spectrometer in a lab. By contrast, the new device can be carried out into the field and used on the leaves of numerous plants, where they're growing.
Along with detecting malnutrition via low nitrogen levels, the sensor can also identify other problems by measuring the levels of other metabolites. If a plant has unusually low levels of pigments known as carotenoids, for instance, it may be suffering from shade avoidance syndrome – this occurs when shaded plants grow tall and spindly in order to reach the sunlight, reducing leaf development and producing structural weaknesses in the process.
"The sensor was demonstrated on multiple vegetable varieties and supports the effort to produce nutritious, low-cost vegetables" says Prof. Nam-Hai Chua, co-Lead Principal Investigator at SMART-DiSTAP and Deputy Chairman at Temasek Life Sciences Laboratory. "Extension of this work to a wider variety of crops may contribute globally to improved crop yields, greater climate resiliency, and mitigation of environmental pollution through reduced fertilizer use."
A paper on the research – which is being co-led by Prof. Rajeev Ram, Principal Investigator at SMART-DiSTAP – was recently published in the journal Scientific Reports.