Abstract:

In protected agricultural systems, fluctuations in crop rhizosphere temperature exert significant impacts on key physiological processes, including water uptake, nutrient translocation and photosynthetic activity. Although contemporary environmental control technologies focus primarily on air temperature optimization, while precise management of rhizosphere temperature, they remain challenged by dual constraints: inadequate adaptability to extreme climatic conditions and subpar energy efficiency. This study systematically evaluated the research advancements and development trajectories of rhizosphere temperature regulation technologies through an integrative bibliometric analysis and technical characteristic comparison, with the aim of clarifying the application frontiers and efficiency enhancement strategies for passive and active regulation approaches. The core objective was to address the conflict between the risk of rhizosphere temperature runaway under extreme climatic conditions and the high energy costs inherent in temperature control systems. Findings indicated that passive regulation techniques, including plastic mulching, ridge cultivation and phase−change materials, mitigated root temperature fluctuations by 40%−60% via physical barrier effects, delivering significant energy−saving benefits under conventional climatic conditions (reducing greenhouse energy consumption by 60%−80%). However, during low−temperature or high−temperature events, the rhizosphere faced an elevated risk of temperature control failure, with the probability of such failure positively correlated with the extremity of climatic conditions. Conversely, active regulation systems, comprising heat pump technologies, active thermal energy storage, release devices and nutrient solution circulation temperature control, enabled precise temperature management within a range of±1°C, enhancing greenhouse crop yields by 17%−55%. These systems were constrained by technical bottlenecks, including a low coefficient of performance (COP 1.5−1.9) and high energy consumption costs (0.7−5.0kWh·m⁻²) per unit area. Future research should prioritize the deep integration of IoT sensing with multi−energy complementary technologies, the development of composite energy storage materials with tunable phase−transition temperatures (15−25°C), and the construction of a full−chain technical framework that integrates climate warning, dynamic compensation, and intelligent control. Such efforts will facilitate a paradigm shift in protected−crop rhizosphere temperature management, enabling a transition from rudimentary buffering strategies to adaptive smart regulation systems.

Key words: Root zone temperature, Facility crops, Passive regulation, Active regulation