Certified Landscape Irrigation Auditor

Which factor is NOT one of the five weather elements that affect irrigation schedules?

1. Sunlight

2. Soil temperature

3. Humidity

4. Rainfall

The correct answer is: Soil temperature

The factor that is not considered one of the five weather elements that affect irrigation schedules is soil temperature. The key weather elements that directly influence irrigation practices typically include sunlight, humidity, rainfall, wind, and temperature (air temperature rather than soil temperature). Sunlight impacts the rate of evaporation and transpiration from plants, which in turn influences the amount of water needed. Humidity levels affect evaporation rates; higher humidity generally leads to decreased evaporation. Rainfall directly determines the necessity and volume of irrigation required because it contributes to soil moisture levels. While soil temperature can influence plant growth and health, it is less directly associated with the timing and scheduling of irrigation compared to the other weather factors. Therefore, recognizing soil temperature as not being one of the primary weather-related factors affecting irrigation schedules is important in understanding efficient irrigation management.