NUTRIENT MAPPING OF NAGARI MANDAL IN CHITTOOR DISTRICT OF ANDHRA PRADESH USING REMOTE SENSING AND GEOGRAPHICAL INFORMATION SYSTEM (GIS)
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Date
2017
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Acharya N.G. Ranga Agricultural University
Abstract
A study was undertaken to assess the soil fertility status, delineate the
spatial variability of soil fertility status in order to suggest fertilizer
recommendations, for Nagari Mandal in Chittoor district of Andhra Pradesh state
using remote sensing and GIS techniques.
Composite surface soil samples (0-15 cm) were collected across the Nagari
mandal using Arc map software with the grid size of 10ha. The GPS data at each
sample location was collected. Ground truth analysis indicated that soils of the
study area are moderately to highly alkaline and with safe EC ranges. The
available nitrogen content of the soils varied from 43.9 to 181.81 kg ha-1, with a
mean value of 77.20 kg ha-1 and standard deviation of 31.7 with CV of 41.08 per
cent, the available phosphorus status in soils was low to high range and ranged
from 2.08 to 133.13 kg ha-1, with a mean value of 29.36 kg ha-1 and standard
deviation of 17.7 with CV of 60.29 per cent and the available potassium content in
soils of Nagari mandal ranged from 64.6 to 753.17 kg ha-1, with a mean value of
217.56 kg ha-1 with standard deviation of 119.5 and CV of 54.93 per cent The
available copper, nitrogen, phosphorous and potassium content showed much
variation with high coefficient of variation. Soils vary across fields and within the
fields. Hence to prove this fact, studies were done at village level taking Tadaku
village of Nagari Mandal where much variability was observed. The data revealed
that CV was high for EC content (83.32%), all other nutrients also observed high
values of CV confirming the existence of spatial variability within field.
It can be inferred that when average content of micronutrients is analyzed,
soils exhibit sufficient status of micronutrients but the coefficient of variation for
available Fe, Cu, Zn and Mn is 52.4, 92.39, 45.23, 40.32 per cent respectively. The
larger CV depicts that within a village there is much variation in the micronutrient
status, proving that soil fertility is not homogeneous. Spatial variability of soil
properties was studied and maps were generated using geo-statistics. In the present
study the variability is observed in case of all the nutrients under study with more
variation in copper followed by phosphorous, potassium, iron, nitrogen, zinc,
manganese, and copper.
The soil site suitability maps for rice and sugarcane delineate the areas in to
suitable and not suitable which could be utilized for selecting the proper cropping
pattern at local level. Suitability analysis of rice crop in study area indicated 585.6
ha is highly suitable (S1), 1156.8 ha is moderately suitable (S2) and 244.8 ha is
marginally suitable (S3). the remaining area 412.8 ha is having severe limitations
that preclude the growing of rice making it not suitable (N), suitability analysis of
sugarcane crop in Nagari mandal indicated that about 295.2 ha is highly suitable
(S1), 1188 ha is moderately suitable (S2) and 628.8 ha is marginally suitable (S3).
The remaining area 288 ha comes under suitability class of not suitable (N).
Site specific fertilizer recommendations for rice and sugarcane in Nagari
mandal are made utilizing the thematic maps of spatial variability of N, P and K
status. The recommended doses of nitrogen for rice crop is 91 and 101 kg ha-1
,
recommended doses of phosphorus are 50, 61, 71, 82 and 93 kg ha-1 and the
recommended doses of potassium are 5, 15, 25, 35, 45 and 55 kg ha-1. The
recommended doses of nitrogen for sugarcane crop is 276, 244, 212 and 180 kg
ha-1, recommended doses of phosphorus are 76, 55, 33 and 12 kg ha-1 and the
recommended doses of potassium are 148, 135, 121,108, 94, 81 and 67 kg ha-1
.
The application of N, P, and K as per the above recommendation in different
spatial zones arrived reveals that there is a significant reduction in fertilizer
application when compared to the general recommendations
In conclusion, it can be summarized that new technologies of 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
with various models in the present study was highly useful in generating the soil
suitability assessment, fertilizer recommendation maps, soil quality assessment
and preparation of customized fertilizer formulations. These studies can be made
up to village level for micro level management of crop fields which help in
attaining sustainability by catering the actual requirement of soil and crop within
spatially variable fields. Further, the results provide actual estimates of fertilizer
requirement for the study area for the important crops grown, thereby saving
budget on nutrients at both planning and farmers level.
Description
D5529
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