What tool can be used to determine the right amount of water needed for irrigation?

A moisture sensor is a valuable tool for determining the right amount of water needed for irrigation because it provides real-time data about the moisture content in the soil. By measuring the soil's water levels, the moisture sensor helps in making informed irrigation decisions. This ensures that plants receive the optimal amount of water—enough to maintain health and growth while avoiding overwatering or underwatering, which can lead to plant stress or disease.

In contrast, a timer primarily controls the duration of irrigation but does not assess the actual water needs of the soil. A soil compactor is used to prepare soil and increase its density, which does not relate to measuring water needs. A pH meter measures the acidity or alkalinity of the soil but does not provide information on water content or irrigation requirements. Thus, the moisture sensor stands out as the most effective tool for determining irrigation needs based on soil moisture levels.