Which meteorological factor primarily affects soil moisture content?

Precipitation is the primary meteorological factor that affects soil moisture content because it directly contributes water to the soil. When rain falls, it seeps into the surface layers of the soil, replenishing moisture that may have been depleted through evaporation or plant uptake. This addition of water is crucial for maintaining optimal moisture levels necessary for plant growth and soil health.

Humidity, while it can influence the rate of evaporation from the soil surface, does not add moisture directly and therefore plays a secondary role compared to precipitation. Temperature affects the rate of evaporation and metabolic processes in plants and microorganisms but, like humidity, does not contribute moisture directly. Wind speed can influence evaporation rates as well, but it primarily acts as a variable that modifies moisture loss from the soil rather than supplying it.