Rapid soil testing and site specific nutrient management are the keys to improve agricultural production sustainably to feed the growing global population, which is projected to cross 9 billion by the end of 2050. A number of soil nutrient sensors are being developed to meet the demand. This paper is focused on the various recent developments in the field of soil nutrient sensors and their sensitivity for particular nutrients. The incorporation of these sensors to develop agriculture decision support systems is also been discussed. It may be concluded that it is better to integrate a number of sensors (optical and electrochemical) to obtain real time data on nutrient level in soil for a particular cropping season to provide the farmers with a real time report and support. Technologies to convert the results into farmer friendly reports and databases to store the real-time data are also very much essential. The entire study is summarized to have an idea of the development in the field of soil nutrient sensors globally in order to gain insights for the sustainable agricultural production in developing countries, such as India, where cost and population are the governing factors.