Certified Landscape Irrigation Auditor

What does the term 'plant available water' refer to?

1. Water lost during evaporation

2. Water stored within the root zone

3. Water absorbed by leaves

4. Water available for irrigation only

The correct answer is: Water stored within the root zone

The term 'plant available water' specifically refers to the volume of water that is stored within the root zone of a plant, which is crucial for its growth and development. This water is accessible to plants for uptake through their roots. It is often defined by the water retained in the soil that the plant can utilize, typically lying between the field capacity (the maximum amount of water the soil can hold) and the permanent wilting point (the level below which plants can no longer extract water). Strong root zone water retention not only promotes healthy plant growth but also contributes to overall irrigation efficiency, as it involves understanding how to manage and monitor the moisture levels in the soil to prevent over- or under-watering. With this knowledge, landscape irrigation auditors can better design and implement effective irrigation strategies that optimize water resources while meeting the needs of the plants. In contrast, aspects such as water lost during evaporation, water absorbed by leaves, and water available for irrigation alone do not accurately represent the concept of 'plant available water' as their functions and contexts serve different purposes related to water usage and management.