CHARACTERIZATION, CLASSIFICATION AND EVALUATION OF SOILS OF PUTTUR MANDAL OF CHITTOOR DISTRICT, ANDHRA PRADESH
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Date
2017
Authors
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Acharya N.G. Ranga Agricultural University
Abstract
The present investigation involves characterization, classification and
evaluation of soils in Puttur mandal of Chittoor district, Andhra Pradesh. For
this, seven representative pedons were selected in seven different locations of
the study area covering all types of soils. All the seven pedons were described
for their morphological features in the field and horizon-wise samples were
collected and analyzed in the laboratory for physical, physico-chemical and
chemical properties.
The study area was characterized by semi-arid monsoonic climate with
distinct summer, winter and rainy seasons. The Pedons selected were located
on nearly level (0-1%) very gently sloping (1-3%) and gently sloping (3-5 %)
topography. All pedons were developed from granite-gneiss parent material.
The morphological features indicated the presence of AC (Pedons 4 and 5),
A-(Bw)-C (Pedons 1 and 7) and A-(Bt)-C (Pedons 2, 3 and 6) profiles. The
soils were deep to very deep in depth, dark reddish brown to very dark grey in
colour, sand to clay in texture and had single grain, sub-angular blocky and
angular blocky structure.
The clay content showed no specific trend with depth in all pedons.
Physical constants like water holding capacity exhibited an increasing trend in
pedon 2 and a decreasing trend in pedon 4 with depth. However, remaining
pedons showed an irregular trend with depth. Loss on ignition showed an
increasing trend in pedon 5 and remaining pedons did not show any particular
xiv
trend with depth. Bulk density showed an increasing trend in pedon 2 whereas
remaining pedons did not show any particular trend with depth.
The pedons were slightly acidic to moderately alkaline in reaction, nonsaline
and low in organic carbon. All the pedons registered low CaCO3 status.
CEC values were low to high and exchange complex was dominated by Ca+2
followed by Mg+2, Na+
and K+
. Chemical composition of soils revealed that all
the pedons had high silica content indicating siliceous nature.
Regarding nutrients status, the soils were low to medium in available
nitrogen, low to high in available phosphorus, medium to high in available
potassium and deficient to sufficient in available sulphur. However, the soils
were deficient in DTPA- extractable zinc (except Ap horizon of pedons 1, 2, 3
and 5) and sufficient in DTPA-extractable copper, manganese and Iron (except
pedon 7).
Based on morphological, physical, physico-chemical, mineralogical and
meteorological data, the soils of Puttur mandal were classified as:
Pedon 1 : Fine-loamy, smectitic, isohyperthermic, Typic Haplustept
Pedon 2 : Fine, mixed, isohyperthermic, Ultic Haplustalf
Pedon 3 : Fine-loamy,mixed, isohyperthermic, Ultic Haplustalf
Pedon 4 : Fine-loamy, siliceous, isohyperthermic, Typic Ustifluvent
Pedon 5 : Fine-loamy, siliceous, isohyperthermic, Typic Ustifluvent
Pedon 6 : Fine-loamy, mixed, isohyperthermic, Ultic Haplustalf
Pedon 7 : Coarse loamy, smectitic, isohyperthermic, Typic Haplustept
Based on the soil properties, the soils of the Puttur mandal have been
classified into land capability classes and sub-classes viz., IIs (Pedons 2 and 7),
IIIe (Pedon 1 and 4), IIIwe (Pedon 5), IVe (Pedons 3 and 6).
The soil-site suitability evaluation of study area revealed that pedons 4
and 5 were marginally suitable (S3) for rice and sesame crops. Pedon 4 was
moderately suitable (S2) whereas pedon 5 was marginally suitable (S3) for
groundnut crop. However, pedon 4 was highly suitable (S1) and pedon 5 was
moderately suitable (S2) for growing sunflower. Pedons 1 and 7 were
moderately suitable (S2) for groundnut and marginally suitable (S3) for rice,
sesame and sunflower. Pedons 2 and 3 were marginally suitable (S3) for
growing sesame and moderately suitable (S2) for groundnut. Pedon 2 was
moderately suitable (S2) and pedon 3 was marginally suitable (S3) for rice.
Pedon 2 was marginally suitable (S3) and pedon 3 was moderately suitable
(S2) for growing sunflower. However, pedon 6 was marginally suitable (S3) for
growing rice and sunflower and moderately suitable (S2) for growing groundnut
and sesame.
Description
D5531
Keywords
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