Wet bulb dimensions associated with different flow and terrain declivity

Geometry information of wet bulb is important for the design of projects and management of drip irrigation, mainly to estimate the volume of wet soil, emitter flows and irrigation time. This study aims to determine the dimensions of wet bulb formed by drippers with different flow and terrain declivities. For this, soil moisture levels were determined throughout the soil profile after drip irrigation with three flow emitters associated with four terrain declivities. It was verified that when the terrain was in level, there was greater radial migration of water on the soil surface with increase in the flow dripper, resulting in more open wet bulbs. On the other hand, increases in flow and declivity provide lower vertical percolation of water, obtaining smaller depth of moisture in the soil profile. Therefore, different terrain declivities and flow drippers influence wet bulb geometry and moisture distribution, indicating the importance of relief in the positioning of emitters in drip irrigation.   Key words: Trickle irrigation, drippers, soil moisture.