The main source of minerals is the soil. The collected nutrients are used to build tissues and important biopolymers, such as proteins or nucleic acids, and participate in many metabolic processes .
The analysis of the chemical composition of the soil can provide a lot of information – for example, on the condition of plants and can be used to determine the state of environmental pollution [2,3,4]. Soils are also used by humans to grow crops. Therefore, their quality is an important issue – good soil quality allows for high yields.
Soil quality is assessed on the basis of physical, chemical and biological parameters. However, soil testing with traditional methods is costly and time-consuming. Therefore, soil quality monitoring using IoT technology is an important element, serving, among others, to improve and develop agriculture, as well as environmental protection. IoT technology is based on the use of various sensors, e.g. humidity, pH (Fig. 1). The sensors are connected wirelessly (Fig. 2) to the firmware that receives data from them. Sensor data is collected and stored on a server or in the cloud. Then, the collected data is analyzed (Fig. 3). Based on the analysis of the data, the farmer can – for example, determine the plant nutrient needs so that the farmer can apply the appropriate fertiliser; choosing the right plants by analyzing the type of soil; irrigate the soil remotely, apply plant protection products. Soil testing using it allows for real-time soil monitoring, helps to reduce cultivation costs or the amount of pesticides used, which ultimately increases overall production [5,6].
Fig.1 IoT sensors for soil monitoring 
Fig. 2 Examples of wireless communication protocols 
Fig. 3 Soil monitoring using IoT infrastructure .