Yes. A land creature is a creature, mana skills are skills, and Humility removes all skills from all creatures.

A creature is a creature, it doesn’t matter what different varieties it could have:

300.2. Some objects have a couple of card kind (for instance, an artifact creature). Such objects mix the points of every of these card varieties, and are topic to spells and talents that have an effect on both or all of these card varieties.

Mana skills are skills:

605.1. Some activated skills and a few triggered skills are mana skills [..]

The inherent mana potential of lands with a primary land kind, similar to Dryad Arbor, might be handled as if it was printed on the cardboard:

305.6. [..] An object with the land card kind and a primary land kind has the intrinsic potential “{T}: Add [mana symbol],” even when the textual content field doesn’t truly include that textual content or the article has no textual content field. [..]

In the layer system that determines an object’s traits, its base characterstics (the copiable values) are set in layer 1, animation results occur in layer 4, and at last Humility removes all skills from creatures in layer 6:

613.1a Layer 1: Rules and results that modify copiable values are utilized.

613.1d Layer 4: Type-changing results are utilized. These embrace results that change an object’s card kind, subtype, and/or supertype.

613.1f Layer 6: Ability-adding results, key phrase counters, ability-removing results, and results that say an object can’t have a capability are utilized.

Therefore, Humility removes the mana-generating potential from land creatures, whether or not they’re inherently creatures similar to Dryad Arbor or they’ve been animated in any other case.