THE ROLE OF PARENT MATERIAL ON SOIL PROPERTIES IN SLOPING AREAS UNDER TEA PLANTATION IN LAHIJAN, IRAN

Abstract

Slope and parent materials play critical roles in determining the soil erosion level. In this study the effects of slope position and parent material on soil properties of tea gardens were investigated in Lahijan, Guilan province, Iran. Four profiles on two different parent material based sites (i.e. granite and phyllite) were selected. Soils were classified as Typic Udorthents, Typic Dystrudepts, Inceptic Hapludalfs and Ultic Hapludalfs, respectively. Results showed that parent material had a significant effect on thickness of the solum and properties such as sand, clay, soil moisture percentage, pH, CEC, total exchangeable bases and base saturation values and the effect of slope position on properties such as electrical conductivity, organic carbone, phosphorous and total nitrogen was noticeable. Soil micromorphology results showed that quartz lithorelicts (rock fragments) and various Fe/Mn oxide nodules were abundant in all soil thin sections derived from granite parent material. The accumulation of illuvial clay as clay coatings and infillings inside the voids was major micromorphological evidence in soils derived from phyllite parent material. Soil development in those derived from phyllite parent material was higher than soils derived from granite parent material. Generally, it seems that parent material had greater effect on properties of soils and soil development than slope position.