Predicting The Depletion Level of Cultivation Area on Dry-Land Agriculture Ecosystem Along Thewatershed Of Serayu River Central Java (A case study along the sub Logawa river bank)

Current study was aimed to explore the depletion levels in agricultural areas due to erosion as well as the appearance of critical soil along the sub watershed of Logawa river by applying a descriptive study using tabulations and SEM-LPS analysis. For these purposes, some physical variables including lengthand slant of the slope; chemicals: soil acidity; and biotic such as microorganisms; social-cultural: local people lnowledge and habbits. Soil samples, were taken from different altitude and mentioned as stratum 1(0-150m alt at 109o 13' 4" EL and 7o 29'45' SL); stratum 2 (150-300 m alt, 109o 11'20" EL, and 7o 23'7" SL) while stratum 3 (300-450 m alt, 109o 10'58", and 7o 20'41" SL). Soil samples were analysed in the laboratory, byt the soil depletion levels were calculated according to Rx K x LS x C x P. Samples in term of farmers were analysed based on a Forum Group Discussion data, including knowledge, habbits and behaviour applying a scheduled questionaire and inteview guide. In order to know the relationship between nowledge , habbits and behaviour and the soil depletion levels data were score and analysed using s Partial least Square Structural Equation Modelling (PLS-SEM). the study showed that the erosion level in the upstreamwas cathegorised as severe i.e.: 158.79 tons/ha/year, middle 280.88 tons/ha/year was strongly severe; and downstream 107.38 tons/ha/year as severe.The main factor of this depletion was human ctivites as well as high rain falls.