[Prosiding IAGI 2007] - 2007-JCB-277
THE STUDY OF LANDFORM TOWARD EROSION IN JEPARA REGENCY
The study of landforms count for a method that good enough in soil loss by water or erosion identification. The landforms include a complete information of soils; their formation time, their development processes and their surrounding feature associations. The landform describes the five formation factors relationships: morphology, morphogenesis, morph chronology and morph process, and morph-arrangement. The Jepara regency has four landforms base on their morphologies, their generation, chronologies, and other processes. They are volcanic, denudational, fluvial and marine landforms. The four landforms have different resistance on rain fall and run off eradication. The volcanic landform has
small rain fall and run off resistance, easy to be eroded. It can be seen from the obvious scrub on the ground, and steep valley formed. The soil loss of volcanic landform belongs to medium to very high class. Its conservation depends on its land covers and how people manage it. The denudational landform has low water damage resistance. It is because of the existent of continuous rotten / decay process that influent rocks easy to be scrubbed and flushed by rain fall and run off water, included the main soil materials. The denudational landform in Jepara area has been developed. Its erosion level can be classified in medium to heavy depended on its land covers. This soil characteristics is easy to be eroded or erosion sensitive. The fluvial landform is dominated by sediment or a-gradation process. The erosion process results are accumulated in the fluvial landform. River is a very important factor on sediments transportation. The soil formed in the fluvial landforms usually has smooth texture. The erosion in this regency is classified in light to very light. The marine landform is a landform dominated by marine processes. The marine landform usually is associated by beach and seashore. The marine processes that influence the landform are sea wave, wind, sea water stream and tide. The erosion process that occurs in marine landform is specific called abrasion. The erosion caused by sea water will cause recession and acresion. Its erosion level depends on abrasion and acresion. Base on the soil loss general equation calculation, the soil loss in marine landform is very light. It is caused by the plain topography and its porous and fast permeable soil materials.
Keywords: landform, erosion