In irrigation management, what is the purpose of using a soil moisture sensor or tensiometer?

• A. To monitor pest activity in the soil.
• B. To measure soil moisture and help schedule irrigation.
• C. To measure rainfall intensity.
• D. To monitor salinity levels in irrigation water.

Answer: (B)

These tools are used to gauge how much water is in the root zone and how tightly that water is held by the soil, so you can time irrigation correctly. A soil moisture sensor gives the actual water content of the soil, showing if it’s near field capacity or drying out. A tensiometer measures soil water potential (matric suction); when suction increases, the soil is drier and plants start to experience water stress. By monitoring these readings, you can schedule irrigation to maintain soil moisture within a target range, applying water only when needed and at appropriate amounts. This improves water use efficiency, reduces waste, and minimizes leaching. Other options involve pests, rainfall intensity, or salinity, which are not the primary purpose of these devices; they’re specifically used to assess soil water status to guide irrigation timing and amount.