Physico-chemical properties and fertility status of water eroded soils of Sharkul area of district Mansehra, Pakistan

Soil degradation is the major threat to agricultural sustainability because it affects the soil productivity. Present study was conducted in 2008 to evaluate physico-chemical properties and fertility status of some eroded soil series of Sharkul area district Manshera, Hazara division, Khyber Pakhtunkhwa, Pakistan. Six soil series including slightly eroded (Dosera and Girari), moderately eroded (Nakholi and Sharkul) and severely eroded (Ahl and Banser) were selected. Soil samples were collected from surface (0-15 cm), subsurface (30-45 cm) and substrata soil (60-75cm) depths and were analyzed for various soil properties. Due to severity of erosion, bulk density increased, while total porosity, saturation percentage and organic matter decreased significantly. AB-DTPA extractable P, K, Fe, Cu, Zn, and Mn concentrations were decreased due to the severity of erosion in surface and sub surface soils, whereas in the substrata soils (60-75 cm depth), the effect of erosion was almost non significant. Sub-surface and sub-strata soils were found deficient in available P (< 3 mg kg-1) while available K was in medium range (50-120 mg kg-1). Seventeen percent surface and 33% subsurface samples were deficient in available K. Organic matter (0.42-1.82%) was deficient only in severely eroded soils while satisfactory in moderately and slightly eroded soils All the soils were non saline (EC < 4 dS m-1), pH (7.0-8.6) and slightly calcareous (lime content 0.25-5.20%). Zinc, Fe and Mn contents were low in 44, 39 and 28% samples in surface soils, respectively. The extent of nutrient deficiency was in the order of P > Zn > Fe > Mn. The physical and chemical properties of eroded soils varied significantly and the increasing severity of erosion resulted in corresponding deterioration of soil quality