"Rainforest soil is considerably different from, say, American tallgrass prairie soil. I understand that it is quite difficult to sustain crops on former rainforest lands."
This is true. The nutrients are concentrated in the absolute top layer of soil, that is why so many trees there have large expanded bases. The trees do not have deep roots (no nutrients there) so the trees have large bases for stability and also to spread out as far as possible to gather the nutrients in the thin top layer.
None the less, when Coca Cola bought out Minute Maid, they also bought 12% of the land area of Belize to grow citrus. (The Florida crops are subject to unexpected freezes, that's no way to run a business.)
posted on 09/04/2002 7:29:04 AM PDT
I understand- and it was something of a surprise to learn so- that ground level diversity was quite low in rainforests. One would probably find more species of plants in a Southern decidous forest than a typical lowland rainforest- and the South's Coastal Plain savannahs and bogs have higher diversity than rain forests per square foot (and are mroe asthetically pleasing to my biased eye). I would imagine though that some types of rainforests have richer soil than others-and soils would vary in places. Of course, I have not had the privilege to travel in the lands where such forests grow- would like to sometime. Money and time...
posted on 09/04/2002 6:49:37 PM PDT
Yes. Typically, in tropical rainforest soils there is a thin layer of partially decomposed organic material right at the soil surface, and all of the soil's fertility is contained therein. The mineral portion of the soil below this organic layer is composed largely of minerals highly resistant to weathering; mostly amorphous hydrated oxides and hydroxides of aluminum and iron (Gibbsite, Goerthite, etc). There is virtually no fertility in these minerals. I find the story posted here to be highly suspect. There is, however, a type of soil, naturally occuring, that these people might be referring to. Vertisols are soils composed principally of 2:1 expanding clays such as Montmorillonite. These clays expand as they absorb water when they are wet, and contract and crack when they dry. Organic material is incorporated into the soil by falling into the cracks, and thus these clays appear dark. Montmorillonitic soils have a high cation-exchange capacity (the ability to retain, and slowly release, plant nutrient cations such as Calcium, Potassium, Magnesium, etc), and are generally relatively fertile. These are widespread, though not abundant, in some tropical and temperate regions of the globe, usually in regions that have short rainy seasons followed by long dry seasons. They normally are NOT found in rainforest (humid or perhumid tropical) areas, because the rates of weathering are too high to sustain these minerals for long periods. These people need to have their site examined by competent soil scientists.
posted on 10/19/2003 6:20:47 AM PDT
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