Effect of slope variation on soil physical properties on the northern aspect in sub-tropical chirpine forest at Tret, Murree hills

Soil physical properties such as infiltration capacity, soil moisture contents and soil bulk density were compared on varying slope of Northern Aspect in sub-tropical chirpine forest at Tret, Murree Hills. Slope was divided into three treatments i.e. gentle slope (0-30 %), medium slope (30 60 %), and steep slope (greater than 60 %). A transect line of 100m length was laid along each treatment and replicated 5 times. On each transect line the infiltration rate (cm/hr) was determined with the help of double ring infiltrometer at mid point. Similarly for soil bulk density and soil moisture contents percent, undisturbed soil samples were collected using Galvanized iron sampler of 6cm in length and 5 cm in diameter. Results indicated that steep slope has the maximum average infiltration rate of 10.76 cm/hr, followed by medium slope 9.098 cm/hr and the lowest in gentle slope 6.63 cm/hr. The average soil bulk density of steep and gentle slope was same 2.11 gm/cm3 while it was higher for medium slope 2.19 gm/ cm3. The results of average soil moisture content were higher on steep slope 21.52% followed by medium 15.8% and gentle slope 11.54%. Statistical analysis (F-test) showed that infiltration rate and soil moisture content were significantly higher on steep slope followed by medium and gentle slope. The variation in bulk density on varying slopes was non significant. It was concluded that presence of good vegetation cover (50-60 percent on slopes greater than 60%, followed by 20-30 percent on both 30-60% & less than 30% slopes) on steep slope was responsible for high infiltration rates. The soil was intact too on resulting in less erosion and runoff on the steep slope. The medium and gentle slopes were much degraded by over grazing, faulty land cultivation and stress of timber and fuel wood due to ease of accessibility. For soil and water conservation it is suggested that, the land should be utilized according to its capability class, grazing should be regulated through a proper system, plantation along with protection of local as well as exotic species should be carried out and soil conservation technique should be adopted if lands are to be cultivated.