IIT Kharagpur and ICRISAT develop rapid soil testing method using Diffuse Reflectance Spectroscopy

New Delhi: Researchers at IIT Kharagpur, in collaboration with the International Crops Research Institute for Semi-Arid Tropics (ICRISAT), have developed a method for rapid soil analysis using Diffuse Reflectance Spectroscopy (DRS), aiming to significantly impact smallholder farming systems. This innovation provides a fast, non-invasive, and cost-effective alternative to traditional soil testing, which often relies on laborious wet chemistry techniques.

For years, IIT Kharagpur’s Agricultural and Food Engineering Department has been exploring the potential of DRS technology in agriculture. Their research now confirms that DRS can efficiently measure soil properties, transforming how soil health assessments are conducted. 

Traditional soil testing methods, which involve complex, time-intensive chemical processes, are often impractical for testing large numbers of samples. By contrast, DRS allows for the rapid measurement of soil reflectance spectra in a non-contact manner. The collected data is then converted into key soil parameters using specially designed spectral algorithms.

Once developed for a specific region, these algorithms can analyze soil samples from various fields and over different periods. This approach eliminates the need for chemicals and enables the quick, simultaneous estimation of multiple soil characteristics, making it ideal for large-scale applications.

The study demonstrated that DRS is capable of accurately estimating eight out of 17 critical soil parameters, achieving up to 80% accuracy. The Soil Test Crop Response (STCR) ratings obtained through the DRS method also showed high consistency with conventional methods, with accuracy levels ranging from 43% to 100%.

“This is a great opportunity because most nutrient management strategies are based on STCR ratings and these ratings may be safely estimated using the DRS approach in a very rapid manner,” said Professor B.S. Das of IIT Kharagpur. More than 60% of the new samples tested achieved accuracy rates above 70%, highlighting the potential of DRS for soil analysis at different scales.

Dr. Jacqueline Hughes, Director General of ICRISAT, emphasized, “ICRISAT has been at the forefront of global efforts to advance sensor-based technologies. Our recent work with NIRS-based spectroscopy for soil nutrient analysis, along with this pioneering research towards DRS models for soil analysis, ensures our commitment to deliver rapid and cost-effective alternatives to resource-poor agriculture systems.”

This advancement aligns with ongoing efforts by the IEEE Standards Association to establish global standards for soil spectroscopy (P4005 – Standards and Protocols for Soil Spectroscopy). The broader adoption of this technique could play a crucial role in enhancing food security, promoting sustainable agriculture, and improving the livelihoods of rural communities across India.