[Prev][Next][Index]
Laterite Facts
I recently searched "laterite" on Alta Vista just to see what it would turn up.
The following is an excerpt I found interesting and thought others would too:
The research undertaken by the Soil Survey and Land Use
Organisation, Palayamkottai to develop the red and laterite soil
in Tirunelveli Kattabomman district, has come as a boon to the
people, particularly the farming community.
Unlike black cotton soils, which have uniform topography,
red soils generally occur on gently sloping to undulating land
with the gradient exceeding three per cent. The soil is found on
the surface or deep below. The texture also varies widely from
loamy to clayey. However the soils are generally well-drained.
They are often gravelly due to rock or iron fragments and
secondary iron nodules are also common. The soils show acidic to
neutral reaction. Due to dominance of kandite clay mineralogy,
they possess low cation exchange capacity, low base and nutrient
status and poor organic matter but have a higher amount of iron
and alumina.
{......perhaps Dupla adds something to theirs to increase the CEC?}
For further reads:
{Laterite soils result from laterisation, the process by
which silice is removed leaving the soil enriched with oxides of
iron and alumina. The enriched soil becomes harder due to
dehydration and the hardened mass called `plinthite' appears
vesicular or like a honey comb in structure. The red and laterite
soils are generally not saline or alkaline.
Red and laterite soils (mainly alfisols, altisols,
inceptisols and entisols as per soil taxonomy) are found in
China, India, Argentina, Kenya, Nepal, Uganda, Sri Lanka,
Bulgaria, the Philippines, Vietnam, Bangladesh, Africa, Nigeria,
Australia, Thailand and Pakistan. In India, it comprises 107
million hectares mainly in eastern Madhya Pradesh, Bihar plateau,
Orissa, West Bengal, Andhra Pradesh, Karnataka, Kerala and Tamil
Nadu. In Tamil Nadu alfisols and inclusions of inceptisols and
entisols occur in abundance in Dharmapuri, Salem, South Arcot,
North Arcot, Chinglepet, Madurai, Pudukottai, Dindigul Anna,
Tiruchi, Tirunelveli Kattabomman and Kanyakumari districts.}
Red soils originate from almost all kinds of felsic and
mafic parent material, mostly in tropical, semi-arid to humid
climates with annual rainfall ranging from 500-4,000 m.m. and
mean annual soil temperature between 16oC to 30oC. In order to
categorise the red soils, the Soil Survey and Land Use
Organisation, Palayamkottai, undertook a reconnaissance survey of
the red soil area and identified eight major soil sub groups. The p73
survey being broad based, specific management practices could not
be advocated to the farming community.
Tyson Lee
tyson at phoenix_net
http://tyson.cet.net/~tyson