In the present era of Internet of Things (IoT), data driven decision making is getting much acceptability in industrial and agricultural sectors. Increase in world population and reduction in resources for agriculture have challenged the conventional farming method to optimize the utilization of resources in a statistical way. Therefore, different field parameters need to be collected and correlated to decide the optimum amount of resource to be applied. Estimation of field parameters are possible by visually comprehending the variation in color gradient or by applying multiple specialized sensors for different parameters at the field. Estimation of physical parameters, field parameters and environmental parameters with required accuracy helps to determine the accurate amount of the resource to be applied. Optimization of resources is the key requirement in the present situation which is not possible without the appropriate sensors. In this paper different types of sensing mechanisms have been discussed with their pros and cons to highlight the potential research challenges in current sensing technology.