PREDIKSI EROSI PERMUKAAN DAN EVALUASI KEMAMPUAN LAHAN DENGAN PENDEKATAN GEOMORFOLOGI UNTUK MENENTUKAN PRIORITAS DAN ARAHAN KONSERVASI TANAH DI KECAMATAN KOKAP KABUPATEN KULON PROGO

The land management should be implemented in accordance to the conservation principles in order to make the creation of optimally sustainable and productive land. This research was aimed to (1) to analyze geomorphological characteristics, (2) to analyze the hazard of the surface erosion (3) to analyze the land capability class, and (4) to set priorities and directions for soil conservation based on the erosion hazard information, the land capability class and geomorphological characteristics. The geomorphological characteristics analysis was conducted using morphological, morphogenetic, morphochronological, and morphoarrangement approaches. The analysis of the surface erosion hazard used USLE prediction model and solum thickness approach. The analysis of the land capability class used matching method. The analysis of the priorities anddirections for land conservation was conducted by using the information of erosion hazard, land capability class, and geomorphological characteristics. The results of the research are (1) the research area is divided into 12 landform units with 3 genesis, of which are volcanic, structural and fluvial. (2) The research area is divided into 5 erosion hazard level (TBE) classes i.e. extremely severe with an area of 1400,1 Ha or 19,9%, severe TBE of 1840 Ha or 26,1%, medium TBE of 3125,9 Ha or 44,3%, low TBE of 310,7 Ha or 4,4% andextremely low TBE of 374,4 Ha or 5,3%. (3) The research area is divided into 6land capability classes i.e. class I with an area of 194,3 Ha or 2,8%, class II of 444,1Ha or 6,3%, Class III of 792,3 Ha or 11,2%, class IV of 1671,8 Ha or 23,7%, class VI of 160,8 Ha or 2,3%, class VII of 3779,7 Ha or 53,6%. There are landslides in the research area with the typology of creep, slide, slump, and rockslide. (4) The research area is divided into 3 soil conservation priority classes i.e. priority I with an area of 3855,5 Ha or 54,8%, priority II with an area of 2363,3 Ha or 33,6% and priority III with an area of 822,5 Ha or 11,7%. Priority I is directed on the use of the protected forest and conservation forest, priority II is directed on the use of production forest, garden, farms, settlements, grasses, and priority III is directed to maintain the existing land uses such as irrigated rice fields, rainfeds, farms, garden, and settlements