DELINEATION AND MAPPING OF SOIL CONSTRAINTS AND THEIR EFFECTS ON YIELD AND QUALITY OF MANGO (Mangifera indica L.) IN YSR DISTRICT, ANDHRA PRADESH USING REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEM
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Date
2024-05-22
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Acharya N G Ranga Agricultural University
Abstract
The present study on “Delineation and mapping of soil constraints
and their effects on yield and quality of mango (Mangifera indica L.) in YSR
district, Andhra Pradesh using remote sensing and geographic information
system” was undertaken to identify the soil related constraints and delineate the
spatial variability of soil fertility status in order to suggest fertilizer recommendation
in YSR district of Andhra Pradesh using remote sensing and GIS techniques.
Georeferenced samples (250 Nos) were collected from the study area
following spatially balanced sampling technique. The soil samples were
analyzed for physical properties like texture, colour, bulk density, particle
density, percent pore space and water holding capacity, physico-chemical
properties viz., pH, EC, OC, CEC, and free CaCO3 and chemical properties viz.,
available N, P, K, Ca, Mg, S, Fe, Mn, Zn and Cu. Similarly, leaf samples were
analyzed for total N, P, K, Ca, Mg, S, Fe, Mn, Zn and Cu and fruit samples
were analyzed for per cent juice, juice pH, TSS and vitamin-C. In irrigation
water, quality parameters such as pH, EC, cations viz., Na+
, Ca2+, Mg2+, K+
and
anions viz., CO3
2-
, HCO3
-
, Cl-
, SO4
2-
, RSC and SAR were analyzed.
Sixteen pedons were selected based on the total area of mango grown in
each mandal and were studied for soil properties to know constraints in sub
surface layers of soils.
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The various soil textural classes identified in surface soils were 42.80
per cent was sandy loam, 38.00 per cent was sandy clay loam, 12.40 per cent
was loamy sand, 4.4 per cent was sandy clay and 2.40 per cent was clay loam.
Texture of surface horizons and sub-surface horizons in pedons varied from
sandy loam to sandy clay loam and gravel nature was seen in subsurface layers
of some of the mandals. The colour of the soils in the study area had their
Munsell colour notation in the hue of 10 YR / 7.5 YR / 5 YR / 2.5 YR with
value of 3 to 6 and chroma of 2 to 8. The colour in all pedons varied from very
dark red to dark greyish brown with a hue ranged from 2.5 YR to 10 YR, value
ranged from 3 to 6 and chroma varied between 1 and 8.
The pH of the study area was neutral to moderately alkaline in reaction.
Out of total study area 38.80 per cent was neutral, 41.20 per cent was weakly
alkaline, 19.20 per cent was moderately alkaline and 0.80 per cent was strongly
alkaline in soil reaction. All the pedons of the study area were neutral to
moderately alkaline in reaction. The orchard soils were non-saline in nature as
the EC of these soils was far below 1.0 dS m-1
. The study area soils were low to
medium in organic carbon at surface and low in sub-surface layers. The organic
carbon content decreased with increasing depth.
Out of all the surface soils of mango orchards studied, 80.00 per cent
were low in available N and 20.00 per cent were medium in available N, 5.60
per cent were low in available P, 92.00 per cent were medium in P and 2.40 per
cent were high in P. However, about 32.00 per cent were low in available K,
35.20 per cent were in medium range and 32.80 per cent were in high range.
The higher exchangeable calcium and magnesium status was observed in all
the orchards. In pedons the available nitrogen was ranged from 59.79 to
273.12 kg ha-1
and were low in available nitrogen. The available nitrogen was
significantly and positively correlated (r = +0.514**) with organic carbon. The
available phosphorus varied from 5.05 to 45.05 kg ha-1
. All the pedons showed
a decreasing trend with depth. The available potassium in different pedons
ranged from 49.98 to 512.05 kg ha-1
soil. The lowest value of 49.98 kg ha-1 was
observed in pedon 10 and the highest was 512.05 kg ha-1
. Calcium, magnesium
and sulphur contents recorded sufficient in all the villages of twelve mandals.
All pedons showed an increasing trend with depth for exchangeable calcium
and magnesium whereas deceasing trend with available sulphur and available
micronutrients.
The data on micronutrient status in these twelve mandals of the study
area revealed that copper and manganese content in almost all soils was
sufficient whereas iron (50%) and zinc content (48%) was deficient in the soils
of Veeraballi and T. Sundupalle mandals.
Two per cent of the leaf samples were deficient in N, 8 per cent deficient
in P and 4 per cent deficit in K. N, P, K, Ca and Mg were 42, 12, 14, 2 and 12
per cent low in leaf samples, respectively while N, P, K, Ca and Mg were 4, 50,
16, 18 and 18 per cent were high in leaf samples, respectively. Zn deficiency in
xvii
leaf was the most severe among the 10 mineral elements tested and 90 per cent
of samples were deficient in Zn, followed by Fe (64%), Mn (36%) and Cu
(25%). However, the average leaf content of N, P, Ca and Cu was 1.27, 0.12,
2.39 and 8.9 per cent, respectively, which was within the optimum range. The
correlation between fruit yield, soil pH and CaCO3 in soil was found to be
negative and significant whereas the correlation between fruit yield and soil EC
was found to be negative and non-significant
Fruit yield was positively and significantly influenced by soil organic
carbon content (r = 0.360), because the organic carbon content of the soil had a
significant positive influence on soil N (r = 0.716**).
The soil mineral nutrients like N, P and K influenced the fruit weight
significantly and positively (r = 0.469*, r = 0.446* and r = 0.415*, respectively).
Fruit juice per cent had significant and positive relation with soil N (r = 0.353*)
and P (r = 0.364*). Soil P had a significant and positive correlation with TSS
(r = 0.438*).
The pH of the irrigation water samples collected from mango orchards
of study area varied from neutral (6.77) to mildly alkaline (8.05). The EC of the
irrigation water varied from 0.82 - 3.87 dS m-1 with a mean value of 1.82 dS m-1
.
According to the irrigation water EC classification, 76 per cent of the water
samples were high in salinity with C3 class and 24 per cent of the water
samples were categorized with high salinity (C4 class). The concentration of
major anions of irrigation water collected from all the mango orchards were in
the order of HCO3
- > Cl- > SO4
2- > CO3
2-
and the cations were in the order of
Na+ > Mg2+ > Ca2+ > K+
.
The general constraints that were observed in the soils of mango
orchards were low organic carbon, low to medium available nitrogen and
phosphorus, wide spread deficiency of zinc and iron, low to medium Mn, wide
occurrence of soil alkalinity, calcareousness and poor quality of irrigation
water i.e., high to very high salinity of the irrigation water.
Soil nutrients thematic maps were prepared using remote sensing and
GIS techniques and delineated the soil related constraints. On the basis of
fertility mapping, suitable recommendations were made in the study area in
terms of available nutrients. In conclusion, it can be summarized that the new
technologies such as remote sensing, GIS and GPS have opened a new era in
generating natural resource database to integrate and assess their potential on
spatial basis. Integration of GIS in the present study was highly useful in
identification of soil related constraints spatially and in generating the fertilizer
recommendation maps and soil suitability assessment. Also, by identifying the
soil related constraints in the study area, it made clear that there is a need of
adoption of soil test crop response based integrated plant nutrition system
(STCR-IPNS) and micronutrient recommendations to mango would enhance
the crop productivity, fertilizer use efficiency and alleviate the deficiencies
over long run