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Detection of salt affected soil in rice-wheat area using
satellite image
Faheem Iqbal
Institute of Geographical Information Systems, National
University of Sciences and Technology,
H-12 Campus, Islamabad, Pakistan. E-mail:
faheem.engr@gmail.com.
Tel: 0092-0333-8971239, 0092-051-90854477.
Accepted 13 July, 2011 |
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Pakistan’s agricultural system is predominately irrigated,
which consumes 90% of fresh water resources and contributes
80% to the national production. It is ironic that the
irrigated areas are the ones that are afflicted most by the
twin menaces of waterlogging and salinity. Climate change is
likely to exacerbate this soil degradation process by way of
heavy rainfalls and by increased evaporation, respectively.
Detection of soil salinity is usually done by laborious soil
sampling. A study, to delineate surface soil salinity in the
prime rice-wheat cropping area of Pakistan, was conducted.
The study employed an index-based approach of using optical
remote sensing data in combination with geographic
information system. The effectiveness of different satellite
imagery indicators was examined. Several combinations of the
ratio of signals received in different spectral bands were
used for development of this index. Near infrared and
thermal IR spectral bands proved to be most effective as
this combination helped easy detection of salt affected area
from the non saline area. Results showed that 19% of the
rice-wheat cropping area of Gujranwala district in Rachna
Doab of central Punjab province of Pakistan is salt
affected. These results are in agreement with the published
survey data. Seasonal dependency of salinity was also
analyzed so as to obtain correct classification.
Key words: Salinity, remote sensing index, salinity
index. |
