## 1 Introduction  
The efficient application of wireless sensor networks in agricultural processes contributes positively to the sustainable development of the economy based on agriculture and food production. The effects of these activities also have a positive impact on the ecology. The processes of monitoring ecological and agronomic parameters that enable a precise assessment of the physiological state of crops enable the timely adjustment of agrotechnical measures to reduce the impact of climate change on agricultural production. Wireless systems based on the usage of sensor nodes make processes in agriculture more intelligent because they become more precise, data-oriented, and greatly automated [1]. The broad usage of microprocessors and microcontrollers, which include small sensor nodes that can be self-modifiable, low-cost tooling, and scalability, demonstrates that wireless sensor networks can be used in the digitization of agriculture [2]. As they join a large number of sensor nodes into a network, wireless sensor networks represent the base for an extremely heterogeneous IoT environment in which there are many different technologies and communication standards. Such a heterogeneous environment enables optimal adjustment to different areas of sensor application. Every field of sensor application requires a suitable selection of communication systems and parameters to achieve reliable and energy-efficient communication. The aim of the implementation of wireless sensor networks in test environments is to connect sensor nodes, deployed at different remote locations, to servers used to store and process data in a reliable and energy-efficient manner. To enable applied research aimed at increasing the efficiency of implemented wireless sensor networks, the communication processes that occur within the networks are subjected to testing for the selected scenarios. The analyses include the specifics of communication in different scenarios regarding the need for continuous monitoring of network parameters and real-time communication. The source of energy required for the activities of the sensor nodes is primarily a battery. The sensor nodes can operate from several months up to several years. The battery cycle is affected by numerous different stress factors including temperature, discharge current, charge current, and state of charge ranges. Since the sensor node's battery life cycle is one of the most severely limited resources in the network, for the implementation of the wireless sensor network especially in areas that are more difficult to access and areas that can be accessed less often, which is a typical example in digital agriculture, it is important to consider the optimization of energy consumption and to achieve the maximum possible energy savings. Therefore, in this paper, the configurations of wireless sensor networks concerning the optimization of the consumption of energy are analyzed. Optimization is analyzed in terms of the choice of adequate star-of-stars topology typical for LoRaWAN networks, data collection, as well as the set-up of network radio parameters. As already confirmed by other sources, for example [3; 4], the sizes of the packets sent contribute significantly to energy consumption. Unlike in other studies conducted in this field, for example in [3; 4], in this paper, special emphasis is given to finding the optimal packet size with regard to transmission rate in order to find the most energy-efficient size of the packet to be used in precision agriculture. For that reason, unlike other articles, this article gives an example of the contents of a packet that can be used in precision agriculture in order to prove that the 6-bit packet is sufficient for efficient collection of parameters from the environment and higher energy-efficiency of communication, in contrast to the 11-bit packets used in standard commercially available equipment.