toothless rake for drawing earth
耰 centers on a specific farming tool: a toothless rake used for smoothing and covering soil after sowing. Its meaning is narrow and concrete, tied to agricultural earthwork.
耰 combines the farming radical 耒 (plow/farming tool) with 憂, which likely provides the sound. The character is a phono-semantic compound for a specific agricultural implement.
The left side 耒 is a farming tool, and the right side 憂 looks like a worried face with a hat. Imagine a farmer using a toothless rake to smooth the soil, worried about covering the seeds evenly.
For ユウ, picture a farmer saying 'you' while handing you the toothless rake: 'You use this to smooth the earth.' The word 'you' cues ユウ.