I want to make one land that taps for 20+ mana by enchanting the land with cards that let it tap for additional mana. What is the most mana we can get a single land to tap for (obviously excluding a Gaea's Cradle or Serra's Sanctum with 100 creatures/enchantments on board). Also, do the enchantments that have the tap symbol add mana in addition to the lands original production or do they replace the lands original mana production (i.e. Abundant Growth).
Abundant Growth