Currently it can be quite hit and miss figuring out what soil a crop may require, especially in the case of more ambiguous options such as sugarcane. This could probably be alleviated by adding soil information to the existing NEI handler or to a tooltip (possibly even requiring analysis?)

If you do that, please also include "needs to grow above" information for custom crops.

I will put it in the journal, right now all the seed portraits use farmland as a background texture, I will change that so they use the soil they require as background.

I'm not sure this is the optimal solution. You only can only get the information once you have the seeds, but you need it to mutate it successfully.

I added the soil to the NEI GUI today. It will be in 1.3.