Hubungan Bahan Organik Tanah Terikat Klei dengan Kadar Klei pada Lahan Reklamasi Tambang Emas Martabe

Abstract

Tanah memiliki peran penting dalam mendukung ekosistem dan lingkungan berkelanjutan. Salah satu indikator kualitas tanah adalah kandungan bahan organik tanah (BOT). Tanah di lokasi tambang emas dapat mengalami degradasi lahan akibat proses penambangan yang intensif. Oleh karena itu penelitian ini bertujuan mengetahui kadar klei, BOT terikat klei dan hubungan antara BOT terikat klei dengan kadar klei. Sampel tanah yang digunakan diambil secara komposit pada umur reklamasi 0- 4 tahun, 9-12 tahun dan 9-12 tahun dengan kedalaman 0-15 cm dan 15-30 cm di area lahan reklamasi tambang emas Martabe, Kabupaten Tapanuli Selatan, Sumatera Utara. Analisis tanah dilakukan di Laboratorium Sumberdaya Fisik Lahan, Departemen Ilmu Tanah dan Sumberdaya Lahan, Institut Pertanian Bogor. Penelitian ini mengukur kadar klei, kadar BOT total dan BOT terikat klei, serta dilanjutkan dengan menganalisis hubungan BOT-klei dengan kadar klei menggunakan scatter plot. Hasil penelitian menunjukkan bahwa kadar klei pada semua umur reklamasi dengan masing-masing kedalaman bervariasi dan BOT terikat klei cenderung meningkat seiring bertambahnya umur reklamasi. Namun, proporsi BOT terikat klei terhadap BOT total antar umur reklamasi dan kedalaman meningkat hingga umur 5-8 tahun lalu menurun pada umur 9-12 tahun, sedangkan proporsi BOT terikat klei terhadap kadar klei mengalami peningkatan seiring bertambahnya umur reklamasi dan stabil pada umur 9-12 tahun. Hubungan BOT-Klei dengan kadar klei di semua umur reklamasi ditunjukkan hanya 20%, sedangkan pada kedalaman 15-30 cm hanya 4% variasi BOT terikat klei dapat dijelaskan oleh kadar klei. Hasil ini menunjukkan bahwa hubungan BOT terikat klei dengan kadar klei hanya mampu menjelaskan sebagian kecil BOT terikat klei.

Soil plays an important role in supporting ecosystems and sustainable environments. One indicator of soil quality is the soil organic matter (SOM) content. Soil at gold mines can experience land degradation due to intensive mining processes. Therefore, this study aims to determine the clay content, clay-associated SOM, and the relationship between clay-associated SOM and clay content. The soil samples used were taken compositely at reclamation ages of 0-4 years, 5-8 years, and 9-12 years, with depths of 0-15 cm and 15-30 cm in the Martabe gold mine reclamation area, South Tapanuli Regency, North Sumatra. Soil analysis was conducted at the Land Physical Resources Laboratory, Departement of Soil and Land Resources, Institut Pertanian Bogor. This study measured clay content, total SOM, and clay-associated SOM, followed by analyzing the relationship between clay-associated SOM and clay content using scatter plots. The results of the study indicate that clay content at all reclamation ages varied at each depth, and clay-associated SOM tended to increase with the age reclamation. However, the proportion of clay-associated SOM to total SOM across reclamation ages and depths increased up to 5-8 years of age and then decreased at 9-12 years of age, varies between reclamation ages and depths, whereas the proportion of clay-associated SOM to clay content increases with the age of reclamation and stabilizes at 9-12 years. This is influenced by the increasingly dense vegetation development. The relationship between clay-associated SOM and clay content at all reclamation ages is shown to be only 20%, while at a depth of 15-30 cm it is only 4% of the variation in clay- associated SOM can be explained by clay content. These results indicate that the relationship between clay-associated SOM and clay content can only explain a small portion of clay- associated SOM.