LAND SUITABILITY ASSESSMENT FOR MAIZE IN KRISHNA DELTA REGION OF ANDHRA PRADESH USING REMOTE SENSING AND GIS
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Date
2016
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Acharya N.G. Ranga Agricultural University
Abstract
The present investigation entitled “Land suitability assessment for maize
in Krishna delta region of Andhra Pradesh using remote sensing and GIS” was
carried out to characterize and classify the soils of Krishna delta and to assess the
suitability for maize. The maps depicting the changes in cropping pattern were
prepared using remote sensing data and GIS. Soil samples for characterization,
classification of study area were collected from representative pedons selected
using remote sensing data (LANDSAT-8) and ground truth information. The
samples were analyzed for physico-chemical, physical and chemical properties
using standard procedures and were classified following USDA soil taxonomy
classification (Soil Survey Staff, 2014). Suitability and capability classification
of the study area was carried out as outlined by FAO (1976) and Sehgal (2008),
respectively. The soil map including suitability classes was prepared using ARC
GIS. The yield gap analysis was done using AquaCrop model.
The study on temporal changes in cropping pattern during 1996-97 to
2015-16 revealed considerable reduction in rice-pulse system with corresponding
increase in rice-maize system. The study area was characterized by semi-arid
monsoonic climate with distinct summer, winter and rainy seasons. The soils
were developed from fluvial sediments and coastal sediments. The soils were
deep to very deep, very dark grayish brown to very dark gray in colour, clay to
sandy in texture and single grain to angular blocky in structure. The bulk density
values of the soils were low at surface compared to subsurface layers. Pore
space, water holding capacity, volume expansion and sticky point values varied
according to clay content.
The soils were near neutral to slightly alkaline in reaction, non-saline to
slightly saline, low to high in organic carbon and low to medium in CaCO3. The
CEC values were varied from 3.37 to 66.20 cmol (p+) kg-1 and the exchange
complex was dominated by calcium followed by magnesium, sodium and
potassium. The analytical data of nutrient status of Krishna delta indicated that
the soils were low to medium in available nitrogen, low to high in available
phosphrous and potassium and deficient to sufficient in available sulphur,
sufficient in manganese however remaining micronutrients (Fe, Zn and Cu) were
deficient to sufficient.
Chemical composition of soils revealed silica and sesquioxides were the
dominant fractions followed by calcium and magnesium oxides. The coarse
textured pedons registered high silica content revealed that siliceous nature.
Based on morphological, physical, physico-chemical properties of the
soils and climate of the region the maize growing soils of Krishna delta region
were classified as:
Pedon 1 : Fine, smectitic, isohyperthermic, Typic Haplustepts.
Pedons 5 and 10 : Fine, smectitic, isohyperthermic (calcareous), Typic
Haplustepts.
Pedon 2 : Very-fine, smectitic, isohyperthermic, Udic Haplusterts.
Pedons 3 and 6 : Fine, smectitic, isohyperthermic, Typic Haplusterts.
Pedons 7 and 14 : Fine, smectitic, isohyperthermic (calcareous), Typic
Haplusterts.
Pedon 4 : Very-fine, smectitic, isohyperthermic, Typic Haplusterts.
Pedon 13 : Very-fine, smectitic, isohyperthermic (calcareous), Typic
Haplusterts.
Pedon 8 : Fine, smectitic, isohyperthermic (calcareous), Vertic
Haplustepts.
Pedon 9 : Loamy, smectitic, isohyperthermic, Udic Ustorthents.
Pedon 11 : Siliceous, isohyperthermic, Typic Ustipsamments.
Pedon 12 : Siliceous, isohyperthermic, Oxyaquic Ustipsamments.
The soils represented by pedons 1, 2, 3, 4, 5, 7, 8, 10 and 14 are
moderately suitable (S2) due to moderate limitations of wetness, soil physical
characteristics, fertility, soil salinity and alkalinity while, pedons 6, 9 and 13 are
marginally suitable (S3f) with severe limitations of soil fertility (f) while, pedons
11 and 12 exhibited severe limitations of wetness (w) to maize, soil physical
characteristics (s) and soil fertility (f). Based on the soil properties, the maize
growing soils of Krishna delta were classified into land capability classes and
sub-classes viz., IIIswf (pedons 1, 4, 6, 7, 8, 9, 10 and 13), IIIws (pedons 2, 3, 5
and 14), IVf (pedon 11) and IVsf (pedon 12).
Yield gap of 28 to 58 per cent of observed yield and 21 to 39 per cent of
simulated yield with potential yield was observed in the study area. The yield gap
between potential yield and simulated/observed maize yield was wide in biomass
than kernel. The mean yield gap was found to be lowest in clay textured soils
followed by loamy sand and sand.
Description
D5295
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