## 1 Introduction  
Soil electrical conductivity is a crucial parameter that reflects soil conditions, significantly affecting crop health and yield [1, 2] and influencing several critical plant growth parameters [3, 4, 5, 6]. The rapid acquisition of soil electrical conductivity data provides effective support for precise agricultural management, offering valuable guidance for optimizing agricultural practices. The research on real-time soil electrical conductivity acquisition methods by scholars both domestically and internationally dates back to the 20 th century [7], with sustained high interest in this field. The primary methods include soil solution conductivity measurement, soil electrical conductivity measurement based on electromagnetic induction (EM) technology [8, 9], soil electrical conductivity measurement based on spectroscopy [10, 11], and soil electrical conductivity measurement using the four-terminal method [12]. Among these, the soil solution conductivity measurement offers high accuracy but requires a prolonged detection time, making it unsuitable for monitoring in arid regions. The four-terminalmethod for soil electrical conductivity measurement is currently the most widely used technology, having been thoroughly validated, widely promoted, and extensively applied. With the advances in research into the \"four-terminal method\" for soil electrical conductivity detection, improving measurement accuracy, reducing production costs, enhancing practicality, and minimizing equipment power consumption have become shared goals among scholars and manufacturers globally. The \"four-terminal method\" has evolved from its initial DC principle to the widely adopted AC principle, addressing issues such as sensor electrolysis when buried in soil for extended periods, which previously compromised detection accuracy and sensor longevity. Currently, the principles of the \"four-terminal method\" for soil electrical conductivity detection are well-established. Researchers now focus on optimizing the sensor structural design, detection circuit implementation, and mitigating influencing factors to enhance detection accuracy and practicality across various application scenarios. For instance, [PERSON] et al. [13] expanded the standard four-pin structure to a six-pin configuration, enabling the simultaneous detection of soil electrical conductivity (EC) at two different depths. In this design, the two central pins measure the shallow soil layer EC, the two outer pins measure the deep soil layer EC, and the two middle pins provide the driving current. [PERSON] et al. [14] utilized an STM32 processor as the core, integrating power supply circuits, AC signal source circuits, RMS detection circuits, and other peripheral circuits to develop a discrete component AC \"four-terminal method\" soil electrical conductivity detection circuit. [PERSON] et al. [15] applied the \"four-terminal method\" to field vehicle-mounted soil detection, using a signal generator instead of a constant current source to provide larger amplitude and more stable sinusoidal signals, thereby advancing a soil electrical conductivity detection system based on a digital oscilloscope. [PERSON] et al. [16] introduced a miniature, low-power, real-time, multi-parameter, and cost-effective soil electrical conductivity sensor. Previous studies have utilized the \"four-terminal method\" to investigate soil electrical conductivity acquisition, resulting in the development of several products [17; 18]. Despite these advances, the following three critical issues remain insufficiently addressed:  
1. The detection principle relies on a constant current source, necessitating the use of discrete components to construct the detection circuit. This approach results in low integration, which not only impedes further improvements in detection accuracy but also leads to high power consumption and increased costs. 2. Previous studies have predominantly used needle-type probe structures, which are inconvenient to use with hard soil and are prone to sensor damage. 3.