Which sensor would help determine soil moisture content to schedule watering?

• A. Soil Moisture Sensor
• B. Humidity Sensor
• C. Temperature Sensor
• D. Wind Sensor

Answer: (A)

The key idea is to measure soil moisture content directly to guide when and how much to water. A soil moisture sensor is designed to probe the root zone and provide a reading of how much water is in the soil (often expressed as volumetric water content). That direct measurement lets an irrigation controller decide precisely when to irrigate and how long, helping prevent both overwatering and drought stress.

Humidity, temperature, and wind sensors each capture different environmental conditions in the air or surroundings, not the water content in the soil. Humidity sensors tell you air moisture, which isn’t a direct indicator of soil moisture. Temperature sensors track warmth, which can influence evaporation and plant needs but doesn’t tell you how much water sits in the soil. Wind sensors measure air movement, affecting evaporation rates, yet they don’t reveal actual soil moisture.

So, for scheduling irrigation based on how wet the soil is, a soil moisture sensor is the appropriate choice.