Attapulgite: what it actually does to soil, at what rate, and what its use costs

A Greek mineral with a specific surface area of 220 m2/g and an exchange capacity of 57 meq/100 g. What the field trials on sandy soils showed, why the rate threshold is 6,000 kg per hectare, what the IARC fibre classification means, which particle grade for which use, and why the rise in pH is the main argument against it on Mediterranean calcareous soils.