Can you play a land if you have already played a land but then had your land count reset this turn?

By default, a player may play only one land per turn (CR 305.2). This is tracked by counting how many lands you have played this turn versus how many you are allowed to play. The allowance starts at one, and the count starts at zero each turn.

Some cards — such as Azusa, Lost but Seeking or Oracle of Mul Daya — increase the number of land plays you are allowed, effectively raising your ceiling rather than resetting your count. Other effects, like Explore, grant 'an additional land play this turn,' which increases your allowance by one.

The phrase 'reset your land count' is not standard rules terminology, but if a card specifically says you may play an additional land, or sets the number of land plays you may have to a new total that is higher than how many you've already played, then yes, you can play another land. If your count already equals or exceeds the new allowance, you cannot.

Example: You play a land normally (count: 1, allowance: 1). You then cast Explore, which lets you play an additional land this turn (allowance now: 2). Because your count (1) is less than your new allowance (2), you may play one more land this turn — per CR 305.2 and the specific card's effect.

There is no general rule mechanic that literally 'resets' your land count to zero mid-turn. Effects only ever increase your allowance. So the answer depends entirely on whether the card in question raises your allowance above what you have already played (CR 305.2).