Soil sensors: detailed insight into research updates, significance, and future prospects

Abstract Soil is an important natural resource that requires crucial attention due to its significant role in crop yield. There is substantial ongoing research on soil health, particularly its water retention capability, moisture content, salinity, temperature, pH, concentration of dissolved gases, etc. Technologies have evolved that can remotely monitor soil and track its various parameters without being physically present in the field, using various probes (coaxial impedance dielectric reflectometry sensors, frequency domain reflectometry sensors, time domain reflectometry sensors, gypsum blocks, neutron probes, etc.). These probes are extremely accurate and provide information about the soil’s surface as well as its inner layers with respect to moisture content, salinity, and temperature. Thus, the probes are helpful for farmers in increasing crop yield by adopting an optimum level of irrigation and suitable fertilizers. The usage of soil probes would be helpful for the economical use of water, as well as of chemical fertilizers to subsequently reduce their toxicity to growing crops. Research scientists studying earth and its environmental processes are always keen to know the processes going on inside the soil. These soil sensors buried in different soil horizons are able to provide complete information to scientists’ lab desktops, even without going to the topographical location. These soil probes are kept intact within the soil with no gaps between the soil and probes to obtain an accurate picture of the soil environment. However, the most tedious aspect is to select the right sensor based on the type of soil and the precision required. This chapter details recent developments on soil sensors, data analysis obtained, and their applications in fields, as well as their shortcomings, if any.