Test implementation of a sensor device for measuring soil macronutrients

Continuous cropping without adequate measurement and provisioning of soil nutrient may endanger the sustainability of agriculture. Soil nutrient measurement is greatly required for proper plant growth and effective fertilization. Existing methods of soil testing are costly and time consuming. In this paper, we have developed a sensing system using high precision, wide spectral range Photo Diode (PD), low spectral-width Light Emitting Diode (LED), microcontroller, analog-to-digital converter (ADC) for measuring soil macronutrients. We have integrated a GPRS modem with our sensing unit for remote data collection to a server. A cell of 5.5 mm path length is used to contain soil solutions. The resolution of 0.1-20 mg/100g has been used as standard solution. The test samples are taken from different farmlands and the results are compared with those obtained by a color chart judgement after laboratory analysis. The results found from our proposed system has good level of agreement with the laboratory results.