Soil Units Distribution In Pesing Watershed Bantul, Yogyakarta, Indonesia

ABSTRACT The study was carried out in Pesing Watershed, which is situated in the Eastern region of Yogyakarta Province. This watershed is a sub-watershed of Opak River that has big variation of landforms. Therefore, it is suitable for the study of soil units distribution. The objectives of this research are: (1) to study the landform characteristics and their distribution , (2) to study the soil characteristics and their distribution, and (3) to study the relationships between soil and landform units in the study area. Geomorphological approach was applied to study the soil unit distribution in the study area. Landform units as geomorphological object were identified through aerial photo and topographic map interpretation. Field works as well as laboratory works were intended to check both the results of aerial photo and topographic map interpretations and soil unit identification. The landform units in the study area vary due to morphology, lithology, genesis, morphochronology and morphoarrangement. These landform unit variations control soil units distribution in the study areas. Geomorphological processes have been modifying the landform unit in the different intensity from one to another. These geomorphological processes have been disturbing soil formation processes. Entisols and Inceptisols as well as Lithic sub group soils occur in the landform units with considerable high intensity of geomorphological processes. Alfisols, Verisols, Mollisols as well as non Lithic sub group soils occupy the landform units with low intensity of geomorphological processes. Kata Kunci.: soil - distribution - watershed - bantul- landfor