As a solution to challenges associated with global agricultural productivity, Sustainable Development Goals (SDGs) focus on smart agricultural practices in order to support the global population of 9.7 billion people projected to exist in 2050. This study presents an loT-based smart system to monitor soil nutrients and prescribe fertilizers on real time basis, which measures eight major soil parameters namely moisture, salinity, temperature, electrical conductivity (EC), pH, nitrogen, phosphorus, and potassium. The real-time monitoring capability of the system was confirmed by field experiments conducted on the vegetative stage of the sorghum crops at Rahim Yar Khan, in Pakistan. 10 samples of the soil were taken using the proposed loT device at the depth of 0-6 inches in different locations within the sorghum field. The system was proved to be quicker than the manual soil testing technique in measurements, therefore providing a more precise, real-time observation of soil fertility, decreasing human error, and providing a timely and data-driven decision-making to optimize crop management.