Relation of Elevation, Slope and Soil Chemistry Properties Toward Arabica Coffee Production in Subdistrict of Bonatua Lunasi, Simalungun Regency, Sumatera Utara

Coffee  have a high economic value and become one of the commodities that reaches the world market  but there is depletion of coffee production, especially Arabica coffee which is caused by incompability of  environtmental factors such as elevation, slope and soil chemical properties. This research aims to determine the correlations of elevation, slope and soil chemical properties toward Arabica Coffee Production in Subdistrict of Bonatua Lunasi. This research was conducted from June to September 2018. Data was obtained by a survey system and data samples were taken purposely random sampling. Total of land map units is 8 SPL (land map units) through from overlaying of elevation maps and slope maps with a scale of 1: 80,000. with 6 soil chemical parameters were soil pH, organic Carbon, Available Phosphate, Cation Exchange Capacity, and base saturation (K, Ca, Mg, Na). The results showed a significant correlation of elevation, slope, Organic Carbon, K and Na also an unrealistic correlation of pH, Ca, Mg, P-Available, CEC and Base Saturation toward the production. Production of Coffee Arabica in Subdistrict of Bonatua Lunasi is affected 14% by the elevation and 63% by slope also by soil chemical properties were 8,3% of soil pH, 16% of organic Carbon, 26% of K, 17% of Na, 6% of Mg, 0,14% of Ca, 1,3% of Available Phosphate, 5% of Cation Exchange Capacit, and 8,7% of base saturation.                             &nbsp