S [235]. As an example, when the soil moisture content material increases from 9.five to 37.three , the communication distance of sensor nodes decreases by 70 , plus the node burial depth needs to reduce from 35 cm to 15 cm. For AG2UG, the Wortmannin Biological Activity signal transmission distance increases by 3 occasions, whilst for UG2AG, the signal transmission distance only increases by 0.four times [26]. The maximum transmission distance of UG2UG is 40 m, which mainly is dependent upon the soil kind. UG2AG can transmit 10000 m [27], and WUSN using a radio frequency of 433 MHz is feasible in agricultural applications [28]. The Lumasiran Purity parameters which can be crucial to analyze the high-quality of soils contain soil bulk density, soil macro and micronutrients, soil organic matter, pH level, soil water prospective, pesticides, pathogens, and temperature [29,30]. Within the transmission of WUSN node signals in underground soil, the signal strength is impacted by the joint influence of various elements [31,32]. Amongst them, soil moisture content, node burial depth, soil compactness, and horizontal distance between nodes considerably decrease WUSN node signal intensity. For that reason, a mathematical model involving signal strength and numerous soil factors is required to evaluate the transmission traits of WUSN node signals within the soil medium. This work focuses on revealing WUSN transmission rules in soil medium. The goal of this study is to (i) set up a soil test platform within the laboratory to investigate the received signal intensity of WUSN nodes under unique situations of soil moisture content, node burial depth, soil compactness, soil temperature, soil acidity and alkalinity, and horizontal distance involving nodes; (ii) obtain the critical variables affecting WUSN node signal transmission in soil medium; (iii) establish a mathematical model amongst the received signal intensity and crucial influencing variables, and take this model because the attenuation model of your WUSN node signal in soil medium. two. Materials and Solutions This section describes supplies and approaches relevant to this study, which includes study website and test design and style, WUSN nodes, and soil test platform for node signal transmission tests. two.1. Study Website and Experiment Design and style The investigation website is located in Yangling District, Xianyang City, Shaanxi Province (108 07 E, 34 28 N, altitude 43563 m). At this web-site, the annual precipitation is 635.1 to 663.9 mm, and the typical annual temperature is 12.9 C. It belongs towards the warm temperate monsoon sub-humid climate. The soil type is typical Lou soil within the Guanzhong region, as well as the soil is fertile and suitable for the growth of a range of crops [33,34]. The experiment settings in this study are as follows. The array of soil moisture content was one hundred ; the depth of nodes was 300 cm; the soil compactness was 0.5.five kg/cm2 ; the soil acidity and alkalinity was 5; the soil temperature was 100 C, and also the level range in between nodes was one hundred cm. Meanwhile, nine levels have been selected for all these six elements. In the underground transmission test of WUSN node signals, the WUSN node and sink node had been arranged within a soil medium. Thinking of the experimental aspects, theRemote Sens. 2021, 13,3 oforthogonal test method was adopted for the test, and also the received signal intensity information with the sink node had been obtained under different test conditions. The orthogonal tests are shown in Table A1 of the Appendix A. In this study, ferrous sulfate and industrial soda ash have been made use of to regulate the acidity and alkalinity of the soil. Agil.