A Cost Effective and Field Deployable System for Soil Macronutrient Analysis Based on Near-Infrared Reflectance Spectroscopy
Near-infrared reflectance (NIR) spectroscopy is a technique that shows many possibilities in the field of testing chemical and physical properties of soil. This paper is aimed to design a prototype of an integrated optoelectronic sensing system capable of estimating soil macronutrients- Nitrogen (N), Phosphorus (P), Potassium (K), pH and Organic Carbon (OC) which play major role in the process of plant growth. 24 soil samples have been collected from farming fields of Birbhum, West Bengal and calibrated using near infrared reflectance spectroscopy. Partial least square (PLS) model along with Standard Normal Variate (SNV) pre-treatment technique has been developed to extract features from the spectroscopic plot which is required for development of field deployable system. The handheld interface attempted in this paper comprises of a simple soil sieve, the output of which is fed in the optoelectronic system which exposes the sieved soil sample to selected IR wavelengths and processes the photodiode output using ARDUINO microcontroller. The trained PLS model embedded in the microcontroller provides estimation of the essential macronutrients with appreciable accuracy. This indigenous system is expected to enhance the scope of precision agriculture in rural India.
KeywordsNear infrared (NIR) spectroscopy NPK OC pH Partial least squares regression (PLSR) Root mean squares error (RMSE) Standard normal variate (SNV) Optoelectronic sensing system Field deployable
We would like to acknowledge Prof. Rajib Bandyopadhyay and Mr. Somdeb Chanda, Department of Instrumentation and Electronics of Jadavpur University for extending their support in conducting the NIR measurements for calibration. We are grateful to Prof. S. Bhaumik of IIEST Shibpur, who is heading the rural technology project in the Institute for providing the necessary financial assistance.
- 3.Martens H, Naes T (1989) Multivariate calibration. Wiley, Chichester, p 419Google Scholar
- 5.Shi T, Cui L, Wang J, Fei T, Chen Y, Wu G (2012) Comparison of multivariate methods for estimating soil total nitrogen with visible/near-infrared spectroscopy. Springer Science Business Media B.V., pp 363–375Google Scholar
- 7.Dale (2012) Chemometrics tools for NIRS and NIR HSI Review I. Bull UASMV Cluj Agric 69(1):70–76Google Scholar
- 8.Mohapatra AG, Lenka SK (2015) Sensor system technology for soil parameter sensing in precision agriculture: a review. J Agric Phys 15(2):181–202Google Scholar
- 9.Treiman AH, Shelfer TD (2000) Manually portable reflectance spectrometer, US Patent 6043893A, pp 1–10Google Scholar
- 10.Westerman RL, Baird JV, Christensen NW, Fixen PE, Whitney DA (1990) Soil-testing and plant analysis, 3 edn. Soil Science Society of America Book Series, pp 73–228Google Scholar
- 13.Liu W, Upadahyaya SK, Kataoka T, Shibusawa S (1996) Development of a texture/soil compaction sensor. In: Proceedings of the Third International Conference on Precision Agriculture. ASA-CSSA-SSSA, pp 617–630Google Scholar
- 14.An X, Li M, Zheng L, Liu Y, Sun H (2014) A portable soil nitrogen detector based on NIRS. Precis Agric 15:3–16. Springer Science Business Media, New York, pp 3–16Google Scholar
- 15.Lee WS, Bogrekci I (2007) Portable raman sensor for soil nutrient detection, US Patent 2007/0013908 A1, pp 1–12Google Scholar
- 16.Holland KH (2013) Optical real-time soil sensor, US Patent 8,451,449 B2, pp 1–18Google Scholar
- 17.Stone ML, Needham D, Solie JB, Raun WR, Johnson GV (2005) Optical spectral reflectance sensor and controller, US. Patent, pp 1–16Google Scholar