In the current agricultural production affected by the warming effect of the planet Earth and the variability of temperatures and showers, maintaining an optimal level of irrigation and its effective management are important prerequisites for the successful production of agricultural crops. To fulfill this task, more or less sophisticated systems are used, from those where the agronomist, based on a subjective assessment of soil moisture, switches on the irrigation system by touch for an estimated time, through irrigation systems that are switched on automatically in predefined modes of sprinkling length and sprinkling intensity, up to systems already more sophisticated, where the need for irrigation, its intensity and duration is controlled by a central control unit. The irrigated areas are then equipped with a sensor network that monitors the amount and intensity of precipitation, the intensity and duration of sunshine, wind flow, etc., and based on these obtained data, the software of the central control unit is able to predict the irrigation cycle through mathematical modeling.

The determining parameter of irrigation efficiency is the supply of the right amount of water to the soil and its subsequent availability for use by plants. The availability of water for plants is primarily determined by the suction pressure, the measurement of which is difficult to maintain. The porous ends of the suction pressure sensors are fragile and there is a risk of the sensor becoming aerated. For these reasons, it is more appropriate to measure the bulk soil moisture to determine the need for irrigation. Volumetric humidity can be measured by several methods using simple and reliable electronic sensors, without moving parts.

Soil water management varies significantly according to the type and quality of the soil and the commodity grown. For effective irrigation planning, it is also useful to know the soil type, which allows us to predict soil capillarity (water absorption) and water infiltration into the soil. In contemporary agriculture, there are databases of types of agricultural land that can be used to predict irrigation processes in a given location, depending on the location of the cultivated area. The Richards equation can be used to describe the movement of water and water vapor through the soil (Saito, 2006). The Richards equation is a solution tool for numerical methods to efficiently and reliably solve a general nonlinear differential equation in a convection-diffusion-reaction scheme.

The main denominator of the new technical solution described here is the meteorological-pedological unit for supporting irrigation management, which removes the disadvantages of the current state of the art and enables consistent distribution of irrigation management and collection of meteorological and soil data. The meteorological-pedological unit allows soil data to be collected at regular intervals using a sensor network data-connected to a control unit equipped with an internal recording unit with a software tool for analyzing the measured values of soil moisture and other parameters. The data unit enables the connection to the database of soil types and the characteristics derived from them, based on all available data, to model the cycle of water behavior in the soil and, based on these models, to create assumptions for managing a separate or integrated irrigation system. The meteorological-pedological unit also makes it possible to evaluate, not only whether to irrigate, but to determine the soil moisture deficit for a given profile. Furthermore, the meteorological-pedological unit is able to function even without the need to connect to the electrical distribution network and allows the use of sensors from different manufacturers and the use of 3D printed parts.

The meteorological-pedological unit for the support of soil irrigation management solves more efficiently, accurately and continuously the assessment of conditions related to irrigation and thus supplies data for the control and management of the irrigation application process. For this, it uses a combination of the placement of a system of sensors placed in the soil in different soil horizons and in different places and sensors evaluating weather conditions affecting water evaporation or precipitation. Furthermore, for a more accurate analysis, it also uses the geographical data contained in the software module and data on soil types in different locations. In addition, the metrological-pedological unit is fully energy self-sufficient thanks to the use of a rechargeable source of electricity and recharging with solar panels.

The meteorological-pedological unit for supporting soil irrigation management consists of several soil moisture sensors, a sunlight intensity meter and a temperature and air humidity sensor. These sensors are standard mass-produced sensors available on the market. All these sensors are data and electrically connected to the control unit, which is connected to the power source. The control unit is equipped with an internal data storage, an internal chronometer and a software module for storing and archiving data from sensors and controlling irrigation processes. The sensors are arranged one above the other in the unit, and after embedding the meteorological-pedological unit in the soil, the sensors in the soil are thus arranged at different soil depths. The measuring unit is either directly connected to the control unit in terms of data and electricity, or in cases where the unit is equipped with several measuring units, the connection is made via a terminal board. The software module carries instructions for analyzing the measured values from the sensors that are collected in the data storage and for determining the need for soil irrigation, even when comparing these data with the influence of the locally relevant soil type.

In an advantageous embodiment, the internal data storage is a microSD card. The use of a standard manufactured and commercially available microSD card allows, if necessary, to remove the card and transfer data to another external data storage or superior control and evaluation unit, which are currently being developed.