Response of Soil Temperature to Soil Moisture Content and Meteorological Elements with Gravel-Sand Mulching

Soil gravel–sand mulching—an ancient farming method in arid areas—is used to cope with drought by conserving water and improving soil temperature, the latter being a key factor affecting agricultural production. The objective of this study is to ascertain the influence of soil water content and meteorological elements on soil temperature under gravel–sand mulching conditions. Field experiments, analysis of variance, Pearson correlation analysis, and other statistical methods were used to study the effects of varying soil moisture content on soil temperature at 0–25 cm depth under gravel–sand mulching conditions, and to analyze the relationships between meteorological factors and soil temperature during the temperature measurement period. In the 0–20 cm soil layer, the soil accumulated temperature decreased with an increase in soil moisture content, while the change rate of temperature increased. In the test range, the temperature conductivity of 10–15 cm soil increased with the increase in soil water content in the 20–40 cm layer. Under gravel–sand mulching conditions, soil temperature was not only related to air temperature but also positively related to water vapor pressure. When the soil moisture content was high, the soil temperature decreased with an increase in atmospheric evaporation capacity. When the soil moisture conditions were poor, the meteorological factors had an effect of increasing the soil temperature. Under gravel–sand mulching conditions, soil moisture content exhibits a significant negative correlation with both soil temperature and accumulated temperature. Higher soil moisture enhances vertical heat conduction, facilitating heat transfer from the surface to deeper layers. The 10–15 cm soil layer acts as a thermal buffer zone, regulating temperature fluctuations and mitigating extreme heat variations. However, higher air temperature leads to greater heat accumulation, while, in wetter soils, enhanced heat conduction and evaporative cooling lower soil temperature.