Kanuma – Soil of Japanese origin (mineral) from the Kanuma area (land of azaleas in Japan), the main characteristic of Kanuma is having a P.H. acid and perpetuate this acidity for a long period, (contrary to peat which is also acidic but neutralizes itself (alkalizes with watering), this characteristic is due to the fact that Kanuma is acidic by thermal demineralization, which reduces its ability to of alkalinization, ensuring acidity throughout the interval between transplants.
This soil is ideal to be used pure (or in a very high percentage in association with other components) in   azaleas, rhododendrons and all species requiring p. H. Acid.
In areas with calcareous waters (as in the south of Portugal), or when the irrigation water is alkaline, or in species that are not acidophilic and like slightly acidic soils (bouganvilea, citrus, etc...), we can add a percentage ( 10 to 15%) to the mixture of hardwoods to facilitate the absorption of nutrients, avoiding chlorosis (as in the case of iron chlorosis - iron deficiency).