What is the term for separating irrigation zones based on sun and shade?

• A. Geozoning
• B. Hydro-zoning
• C. Thermo-zoning
• D. Exposure zoning

Answer: (B)

Hydro-zoning is the practice of dividing irrigation zones by plant water needs, which are strongly affected by sun and shade. In full sun, evapotranspiration is higher, so plants use more water and require more irrigation. In shaded areas, ET is lower, so less water is needed. By grouping areas with similar water demands into zones, you can tailor irrigation schedules to match actual needs, improving efficiency and preventing over- or under-watering. The other terms don’t fit as well: geozoning relates to soil or geographic factors, thermo-zoning to temperature patterns, and exposure zoning isn’t the standard irrigation term, even though it hints at sun exposure.