CHARACTERISTICS OF THE CHEMICAL PROPERTIES OF SOIL UNDER ULIN (Eusideroxylon zwageri) AND MERANTI (Shorea sp) TREE CROPS IN THE SEMPAJA ARBORETUM FOREST AT GENERAL TESTING CENTER FOR ENVIRONMENTAL INSTRUMENTS IN SAMARINDA

The aim of this study was to determine the chemical and textural characteristics of the soil under Ulin (Eusideroxylon zwageri) and Meranti (Shorea sp) stands in the Sempaja Arboretum Forest, Samarinda Center for Standard Testing of Environmental Instruments. This research was carried out from March–May 2022 at the Sempaja Arboretum covering an area of 2.5 ha which is located in the area of the Samarinda Center for Standard Testing of Environmental Instruments. The research activities carried out included: literature study, field observation, preparation, determination of sampling points, field sampling, soil analysis in the laboratory, interpretation of soil analysis results and reporting. The results showed that: (1) the chemical characteristics of the soil under ironwood stands were: soil pH (very acid), organic-C content (very low), total-N content (very low), available-P content (medium to high ), cation content of Ca++, K+and Na+base cations (very low to low), cation Mg++ (low to medium), CEC and saturation (low), texture class of silty loam soil; and (2) chemical characteristics of the soil under meranti stands, namely: soil pH (very acid), C-organic content (very low to low), content N-total (moderate), available-P content (moderate to very high), cation content of Ca++, K+and Na+basic cations (very low to low), cation of Mg++ (low to moderate), CEC (low), base saturation (very low to low), silty loam soil texture class.  &nbsp