Which irrigation method allows for manual adjustment for specific plant needs?

Hand-held irrigation is the method that allows for manual adjustment to cater to specific plant needs. This technique involves manually directing water to plants, giving the applyer the flexibility to adjust the amount and timing of water based on the unique requirements of individual plants or areas in the garden or field. This level of control can be crucial in situations where certain plants may require more water due to varying soil types, plant sizes, or growth stages.

In contrast, automatic sprinkler systems typically operate on timers and preset programs, which can be less responsive to the immediate needs of the plants. Drip irrigation systems are designed for efficiency and precision, delivering water directly to the roots but may not offer the same level of manual adjustment by the operator as hand-held methods do. Lastly, subsurface irrigation involves placing irrigation lines underground and provides consistent watering but lacks the ability for immediate adjustments based on real-time plant needs and conditions. This further highlights why hand-held irrigation is superior for those requiring nuanced management of water application.