Appropriate Technologies Lab/Soil ph
According to the EWB presentation on 8/13/10, one of the issues they are facing is the fact that the soil is very acidic. This limits the range of plants they are able to grow. Currently they are changing the ph of the soil with powdered limestone. This is a study in how to do this more efficiently.
Here in the US, gardeners use "garden lime" or "slaked lime", Ca(OH)^2. It has a ph of 12.4. The compound being used at the agricultural center is limestone, or calcium carbonate, CaCO^3. It has a ph of 9. The more caustic the compound, the less of it that has to be used to raise the ph of the soil to the proper level.
Slaked lime is created by burning limestone, giving you calcium oxide CaO, and then hydrating it by letting it sit in water. The advantage to this is that you don't need as much to do the same amount of work (as noted above) and you don't have to build a rock crusher to powder the limestone as the act of burning it will powderize it for you.