Inventarisasi dan Evaluasi Sifat Kimia Tanah pada Sistem Agroforestri di Kecamatan Lumban Julu Kabupaten Toba

Abstract

The conversion of forest land into agricultural land causes many problems for the environment. The agroforestry system is a system that optimizes land use, which is expected to be able to overcome these problems. Currently, there are not many farmers who apply agroforestry systems, especially in Lumban Julu District, Toba Regency. This study aims to identify agroforestry types in Lumban Julu District of Toba Regency, evaluate soil chemical properties in each type of agroforestry, monoculture agricultural land, and forest land. The study uses a survey method with purposive sampling technique. Soil samples were taken at 8 coordinate points with a depth of 0–30 cm. Furthermore, soil samples were analyzed in the laboratory. The analysis of soil chemical properties consisted of H2O pH, C-organic, Cation Exchange Capacity (CEC), total N, soil available P, total K, and C/N, then the analysis results were described based on the criteria of the Bogor Research Institute, 2005 on each parameter. The results obtained show that the agroforestry system found in Lumban Julu District of Toba Regency in terms of its constituent components is the agrisilviculture type, with sub-types of plant combinations PBI (industrial fruit food), PB (fruit food), PIH (horticultural industrial food), BH (horticultural fruit), and BI (industrial fruit). The best soil chemical properties are owned by agroforestry sample LJ2A2 sub-type PB (fruit food) plant combination with criteria of acidic pH, very high C-organic, high CEC, high total-N, very high soil available-P, very high total-K, and low C/N. The criteria for soil chemical properties of the agroforestry systems are overall better than the monoculture farming system.