Re: carissa macrocarpa
Depends on the parent material of the soil. Most of our older Hawaiian
Soils tend to be 6.5 of a iron/alluminium oxide with organics and very
little silica based sand. This soil ties up everything (phosphrus, iron,
etc.) I foreget how many tons of lime per acre are necessary to alter the
pH. In the younger soils that are basaltic gravel/sand based they tend to
have very little buffering and pH isn't a big factor, but nutrient
retention is very poor, however they tend to be naturally high in
magnesium and potassium.
MTF
> shape. Like most Carissa's hereabouts(soil pH approx. 6.8) they are
> showing extreme 'Lime Induced Chlorosis', aka iron deficiency.
> Does our S.African correspondent have any idea what the soil pH is
> in Carissa's native soil? It sounded as if it was desert, but desert soils
> are generally of a very high pH, often over 8.0, so I'm confused. I would
> expect the pH to be low, perhaps 5.5. That would explain why they show
> such iron/zinc/manganese deficiency in our alkaline California soil. But a
> pH of 5.5 would indicate high rainfall, probably 40in or 100 cm/year. Any
> info from SA would be greatly appreciated.
Mach T. Fukada, Editor
Note New E-mail address:
fukada@aloha.net
Honolulu Aquarium Society
http://www.geocities.com/Heartland/Meadows/2948/HASF.html
