CHARACTERIZATION, CLASSIFICATION AND EVALUATION OF SOILS OF PALAMANER DIVISION IN CHITTOOR DISTRICT OF ANDHRA PRADESH FOR SUSTAINABLE LAND USE PLANNING
Loading...
Date
2024-05-23
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Acharya N G Ranga Agricultural University
Abstract
The present investigation entitled "Characterization, classification, and
evaluation of soils of Palamaner division in Chittoor district of Andhra Pradesh for
sustainable land use planning," involved 18 master profiles in three transects with 6
pedons each. The morphological, physical, physico-chemical, chemical, elemental
composition, and available and total macro and micronutrients of these pedons
were examined. The study area had a semi-arid monsoonic environment with
distinct summer, winter, and rainy seasons.
The three transects that make up the Palamaner division's research area are
transect-I, transect-II and transect-III. Pedons 1 and 2 were situated on top slopes
(3-5%), pedons 3 and 4 on middle slopes (1-3%), and pedons 5 and 6 on lower
slopes (0-1%) in transect-I. In a similar fashion, in transect -II, pedons 7 and 8
were found on upper slopes (3-5%), pedons 9 and 10 on middle slopes (1-3%), and
pedons 11 and 12 on lower slopes (0-1%). In contrast, pedons 13 and 14 in transect III were situated on higher slopes (5–10%), pedons 15 and 16 in the centre of the
slope range (3-5%), and pedons 17 and 18 in the lower slope range (1-3%).
According to 30 years of meteorological data, the distribution of rainfall
was essentially symmetric. Rainfall has strong abnormalities, which symbolises
the dry land agriculture in the research region, according to the precipitation
concentration index (PCI), which was determined. The seasonality index was
above 1.2 in some years, indicating that the study area's rainfall was cyclical with
brief dry seasons. The research region comes under the isohyperthermic soil
temperature regime and ustic soil moisture regime based on mean air and soil
temperatures, with a growing season of 90 to 150 days, supporting a single crop.
xxiii
The morphological characteristics of the soils (Transect-I) revealed that the
upper slopes (Kanalillu, P1 and Kummaragunta, P2) had Ap-Bw and Ap-Bt
horizons, while the middle slopes (Chellargunta, P3 and Settipalle, P4) include
Ap-AC and Ap-Bt horizon sequences, and the lower slopes' soils display Ap-Bt
and Ap-B/A-BA-Bt horizon sequences (Gorreladoddi P5, Chinnapuram P6). These
soils have a matrix that ranges from extremely light brown (2.5 YR 8/3) to dark
reddish brown (2.5 YR 3/4), however they were sandy loam to clay loam texture.
Transect-II soils were made up of Atukurallapalle (P7) and Samalagadda (P8) on
the upper slopes, Gangavaram (P9) and Kongavaripalli (P10) on the middle
slopes, Maredupalli (P11) and Jidimakulapalli (P12) on the lower slopes. The soils
on the upper slopes have horizon sequences of Ap-BA-Bt and Ap-A/B-B/A-Bw1-
Bss1, respectively, while the soils on the lower slopes have horizon sequences of
Ap-AB-Bw and Ap-Bw1-Bw2-Bw3-Bw4, and the soils on the middle slopes have
Ap-Bt1-C1-2Bt1 and Ap-Bt1-C1-Bt2. The soils are fairly deep to deep, sandy
loam to clay loam in texture, and dark reddish brown (2.5 YR 3/4) to light grey
(10YR 7/2) in colour. Transect-III soils included Zararipalli (P13), Kilapatla
(P14), Gandhinagar (P15), Mogili (P16), Gourishankarapuram (P17), and Mittur
(P18), and the pedons showed Ap-Bt horizon sequences. These soils were loamy
sand to clay texture with a dark reddish brown (2.5 YR 3/4) to light brown
(7.5 YR 6/4) matrix.
All of the pedons in transect-I have more sand in the top soil, whereas the
deeper layers have more silt and clay. Subsoil layers that had a sand to silt ratio of
less than 1 showed discontinuities that were similar to those found in field
descriptions as well as abrupt shifts like those seen in P1, P4, and P5. P9 and P10,
which have comparable horizon sequences in the soils of transect-II and referred
to as the C1 horizon features abrupt sandy loam horizons interspersed with sandy
clay loam horizons. Sand, silt and clay were present in nearly equal amounts on
the upper and lower slopes of the soils of transect-III. In transects I, II, and III, the
mean bulk densities of the soils were 1.43 Mg m-3
, 1.45 Mg m-3
, and 1.48 Mg m-3
,
respectively. The soils' clay content and water holding capacity tended to expand
in comparable ways.
The soils of transects I, II and III were low to medium in organic carbon,
non-saline, and mildly acidic to neutral. The soils had a C:N ratio that ranged from
4.21 to 11.29 and a CEC of 5.23 to 46.23 cmol (p+) kg-1
. The soils were
predominately composed of exchangeable Ca and exchangeable bases were in the
order of Ca > Mg > K > Na. Regardless of the slopes and transects, the overall
nitrogen content was less than 1 per cent. The total phosphorus concentration
ranged from 184 to 745 mg kg-1
, the total potassium ranged from 2000 to 5167 mg
kg-1
, and the total sulphur ranged from 200 to 960 mg kg-1
in the soils. The total
zinc level in the soils ranged from 18.24 to 60.22 mg kg-1
, whereas the total copper
content ranged from 17.06 to 52.75 mg kg-1
, the total manganese content from
112.64 to 386.26 mg kg-1
, and the total iron from 0.87 to 6.47 mg kg-1
. However,
the soils of transects-I, II and III have low to medium levels of accessible N, high
to medium levels of available P and low to medium/high levels of available K and
deficient to sufficient in available S. DTPA extractable Cu and Mn were sufficient
whereas, the DTPA extractable iron and zinc were deficient to sufficient
irrespective of slopes and transects.
xxiv
Molar ratios and weathering indices were developed from the bulk
geochemical data to comprehend the weathering patterns of these soils. All of the
transects' predominant elemental compositions were SiO2, Al2O3, and Fe2O3. P2O5,
K2O, and Na2O concentrations in all of the soils were less than 1 per cent. The
concentrations of CaO and MgO ranged from 0.82 to 2.67 and 0.22 to 1.62,
respectively. Clayeness (mAl2O3 / mSiO2) and calcification index (CaO + MgO /
Al2O3) were found as two prominent pedogenic processes using molar ratios. The
research area's soils were moderately to extremely worn, according to the CIA
index of soils, which ranged from 74.95 to 87.70 per cent. The soils' Index-A and
B values ranged from 0.82 to 0.91 and 0.11 to 0.21, respectively, while the CIA-K
and WI (weathering index) values ranged from 76.58 to 89.31 and 2.35 to 4.05,
respectively.
The A-CN-K diagram revealed that granite-gneiss samples were situated
above the K-feldspar join, in the centre of the A-K and A-CN lines. This tendency
might be brought on by the removal of Ca and Na through plagioclase
degradation. Illite formation is further aided by the transition of K-feldspar and
illite when kaolinite has not yet formed. The retention of Fe(t) and Mg as
weathering continues is likewise depicted in the A-CNK-FM graphic.
Pedon 3 : Coarse – loamy, mixed, isohyperthermic, Typic Ustorthents
Pedons 1, 8 and
11
: Fine – loamy, mixed, isohyperthermic, Typic Haplustepts
Pedon 12 : Fine, mixed, isohyperthermic, Vertic Haplustepts
Pedons 2, 4, 5,
6, 9, 10, 13, 14,
15, 16 and 17
: Fine – loamy, mixed, isohyperthermic, Typic Haplustalfs
Pedon 7 : Fine – loamy, mixed, isohyperthermic, Typic Rhodustalfs
Pedon 18 : Fine – loamy, mixed, isohyperthermic, Ultic Haplustalfs
The soils of the study area were divided into land capability subclasses viz.,
IIIs (pedon 6), IIIes (pedon 3, 15 and 18), IVs (pedons 4, 5, 9, 10, 11 and 12), IVes
(pedons 1, 2, 7, 8, 13, 14 and 16), and VIes (pedon 17). The study area's soils have
been divided into four land irrigability sub-classes such as, 2s (pedon 18), 3s
(pedons 2, 3, 4, 5, 6, 10 and 15), 4s (pedons 1, 7, 8, 9, 11, 12, 13, 14 and 16), and
6s (pedon 17). According to the evaluation of the soil-site suitability in the
research region, pedons 1, 2, 3, 4, 5, 6, 10, 13, 14, 15, 16, 17 and 18 were not
appropriate (N) for rice, marginally suitable (S3) for groundnut and moderately
suitable (S2) for maize and finger millet. While pedons 7, 8, 9, and 11 were only
moderately suitable (S2) for maize and finger millet, pedons 7, 8 and 12 were only
marginally acceptable (S3) for groundnut. Pedon 12 was also only moderately
suitable (S2) for rice, groundnut and finger millet. The potential productivity of
soils was good to exceptional for most pedons, while actual soil productivity
ranged from ordinary to good. The crop improvement factor varied from 1.43 to
1.58, demonstrating the use of wise soil and water management techniques to
maintain soil productivity