The Effect of Topography on Soil Properties with a Focus on Yield and Quality of Almond in the Saman Area, Shahrekord

This research was carried out to assess the effects of aspect and landscape position on soil properties and the effect of these properties on almond yield and its quality in Saman area, Chaharmahal-va-Bakhtiari province. Samples from topsoil and subsoils (0-40 and 40-80 cm) were collected from three transects in northern aspect and three transects in southern aspect in five landscape positions. Almond samples were collected from two almond trees at each landscape position. At each aspect and on each landscape position, five soil profiles (in total, 10 soil profiles in both aspects) were studied along one transect. The results indicated that surface soil in northern aspect had higher levels of clay, organic matter, soil moisture, potassium and nitrogen in comparison with southern aspect (p<0.05). Yield, quality and some of vegetative properties of trees in northern aspect are higher than southern aspect. Yield decreases at down slope consisting of footslope and toeslope despite the better soil conditions. Decreasing the yield could be due to the frost-bite of almond tree in blossom time. Denser and colder air moves downward the toeslope harming almond blossoms. Differences in soil formation processes resulted in different soil classes according to Soil Taxonomy. In upslope positions, soils were classified as Inceptisols, whereas in down slope positions (footslope and toeslope) were mostly classified as Alfisols. Soil classification at family level could show the effect of soil properties on almond yield and quality. Due to better conditions of soils, northern aspects are recommended for planting almond trees in the region. Also in lower positions, planting frost-bite resistant and late-flowering cultivars, together with heating and sprinkler irrigation would increase almond yield.