Agricraft's SoilWhitelist is used to include any soils you want to be able to plant cropsticks on, and normally would work wonderfully, however: The one block that it adds in Agrarian Skies 2, The MFR Farmland, is incompatible. Attempting to place cropsticks on it still won't work, despite it being whitelisted. This isn't really a major problem, though: Humus (Forestry) and Podzol still work just fine if you want to grow your crops away from a water source.
What about banning it, then? Vanilla farming (Farming without the use of cropsticks) is still possible using it, weren't we trying to avoid doing that? You can't plant seeds on farmland, after all.
MFR's Farmland. It doesn't accept crops like it should, and instead allows vanilla farming--I believe this is coded into MFR itself, but the guy who made that mod didn't include config files, so that cannot be disabled.
It's bypassing the vanilla farming disable! Agricraft was included specifically so you have to farm via crops, but MFR's soil is able to bypass that and allow you to just plop the seeds down and not worry about crossbreeds, weeds, or anything like that.