rich soil; fertile land
Refers to soil or land that is naturally fertile and good for cultivation. Somewhat literary or technical; in everyday speech, 肥沃な土壌 or 肥えた土地 are more common.
This region is blessed with fertile soil, and agriculture thrives.
People migrated to new lands in search of fertile ground.
The kanji 沃 means 'fertile' or 'to irrigate', and 土 means 'soil'. The compound 沃土 directly conveys 'fertile soil'. The reading よくど is the on'yomi for both characters.