Document Type : Research Paper
Authors
1
Soil and water Research Department, Bushehr Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Bushehr, Iran.
2
Associate Prof., Soil Science Department, Faculty of Agriculture University of Shahrekordm,iran
3
Department of Soil Science, Faculty of Agriculture, Shahrekord University. Shahrekord. Iran
4
Soil and water Research Department, Bushehr Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Bushehr, Iran
Abstract
Human mismanagement of soil and land resources to meet food demands has led to increased sediment loads and exacerbated both on-site and off-site problems in watersheds. The Baghan watershed, covering 929 km² with a hot and arid climate, is located in the coastal region of Bushehr Province, Iran. Agricultural expansion, establishment of the Fajr Jam gas refinery, population growth due to migration, and industrial development have intensified pressure on the watershed’s soil and water resources. This study aimed to identify the sources of transported sediments in the Baghan watershed using the sediment fingerprinting method. To this end, 120 sediment source locations were identified using Latin Hypercube Sampling, and 30 sediment samples were collected from confluences of streams, main channels, and sub-watershed outlets during field surveys. Composite sampling included 63 samples from rangelands, 33 from agricultural lands (both rainfed and irrigated), and 24 from orchards, collected from 0 to 20 cm soil depth. Chemical analyses were conducted using standard laboratory procedures. Results from a multivariate composite model based on geochemical tracers indicated that sediment contributions ranked as follows: rangelands > orchards > rainfed agriculture > irrigated agriculture. Rangelands accounted for the largest share (34%) of sediment sources. This high contribution is attributed to the extensive area of rangelands, steep slopes, geological sensitivity of formations, and overgrazing.
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