Liquidity mining at Arable allows you to stake LP tokens for ACRE rewards.
You get LP tokens as a 'receipt' for providing liquidity for a token pair at a DEX such as Pangolin. By providing liquidity, you allow other users of the DEX to swap between those tokens. A DEX charges a fee for each swapping action, and you will get a cut of those fees as a reward.
You can stake those LP tokens at Arable and generate ACRE rewards in return. At the moment, LP tokens for the ACRE/WAVAX pair and arUSD/WAVAX are supported with plans for additional token pairs in the future.
If you decide to unstake, there is an unbonding period of 14 days during which you will not generate any ACRE rewards.
You can find more information on liquidity mining at Arable here: Liquidity mining