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Journal of Applied Sciences and Environmental Management
World Bank assisted National Agricultural Research Project (NARP) - University of Port Harcourt
ISSN: 1119-8362
Vol. 20, No. 4, 2016, pp. 1037-1042
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Bioline Code: ja16109
Full paper language: English
Document type: Research Article
Document available free of charge
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Journal of Applied Sciences and Environmental Management, Vol. 20, No. 4, 2016, pp. 1037-1042
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Investigation of Soil Salinity to Distinguish Boundary Line between Saline and Agricultural Lands in Bonab Plain, Southeast Urmia Lake, Iran
NIKOU, HAMZEHPOUR & MEHDI, RAHMATI
Abstract
Gradual drying of Urmia Lake has left vast saline areas all around it, increasing the risk of
salinization of agricultural lands next to the Lake. The current research was aimed to predict soil salinity and distinguish
the boundary line between saline and agricultural lands by taking in to account the spatial variability of soil salinity in
Bonab Plain, Iran. To do so, soil samples were taken from depth 0-25 cm in 78 points with spatial intervals of 500 m
and were analyzed for their electrical conductivity in saturated paste extractions. Data analysis showed that soil salinity
mean wasn’t stationary and was varying among dataset. Therefore to build up a variogram, the spatial components of the
mean trend were computed and subtracted from laboratory measured ECe values, which resulted in residuals. The semivariogram
function was then calculated and modelled based on the residuals. Cross-validation results showed that
kriging method along with modified semi-variogram, resulted in better predictions of soil salinity with ME and MSE
equal to 0.12 and 0.3. Setting 4 dSm-1 as the limit between saline and non-saline soils in kriging algorithms resulted in a
sharp boundary line between saline and non-saline lands in the study area. The presence of highly saline soils next to the
agricultural lands in the area can increase the risk of secondary salinization of the Bonab Plain which is one of the
important agricultural production centers in the area. Therefore, careful monitoring of lands near salinity boundary in the
area should be of high priority.
Keywords
Bonab Plain; Kriging; variogram; soil salinity; spatial prediction; Urmia Lake
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© Copyright 2016 - Journal of Applied Sciences and Environmental Management
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