Respons Bibit Gaharu pada Pemberian Campuran Asam Humat dan Pupuk Organik pada Tanah Bekas Tambang Kapur

Abstract

Indonesia memiliki sumber daya alam tidak terbarukan seperti batu kapur yang dimanfaatkan dalam industri semen, namun aktivitas penambangan menyebabkan degradasi sifat fisik, kimia, dan biologi tanah. Penelitian ini bertujuan menganalisis respon bibit gaharu terhadap pemberian campuran asam humat dan pupuk organik terhadap perbaikan unsur hara pada tanah bekas tambang kapur, serta menentukan dosis yang paling optimal. Penelitian menggunakan Rancangan Acak Lengkap (RAL) dua faktor, yaitu asam humat (0; 1,5; 2; 2,5 g) dan pupuk organik (0; 100; 200 g). Parameter yang diamati meliputi tinggi, diameter, persentase daya hidup, berat kering akar, berat kering pucuk, dan berat kering total selama 11 minggu. Hasil penelitian menunjukkan campuran 1,5 g asam humat dan 100 g pupuk organik meningkatkan pertumbuhan tinggi (64,09 %), diameter (11,35 %), dan berat kering (94,53 %). Analisis tanah menunjukkan peningkatan C-organik (246,73 %), N-total (275 %), P-tersedia (517,73 %), dan K-tersedia (983,78 %), serta penurunan Ca-tersedia (8,45 %) meski pH tetap bersifat alkalis. Campuran 1,5 g asam humat dan 100 g pupuk organik yang diberikan efektif meningkatkan pertumbuhan bibit gaharu dan memperbaiki kualitas tanah.

Indonesia possesses abundant non-renewable natural resources, such as limestone, which is primarily utilized in the cement industry; however, mining activities severely degrade the physical, chemical, and biological properties of soil. This study aimed to analyze the response of agarwood (Aquilaria malaccensis) seedlings to the combined humic acid and organic fertilizer for nutrient restoration in post-limestone mining soil, as well as to determine the optimal dosage. The experiment followed a two-factor Completely Randomized Design (CRD), comprising humic acid (0, 1.5, 2, and 2.5 g) and organic fertilizer (0, 100, and 200 g). Observed parameters included height, diameter, survival rate, and dry weight over an 11-week period. The results indicated that the mixture of 1.5 g humic acid and 100 g organic fertilizer yielded the height (64,09 %), diameter (11,35 %), and dry weight (94,53 %). Soil analysis revealed significant increases in organic carbon (246,73 %), total nitrogen (275 %), available phosphorus (517,73 %), and available potassium (983,78 %), along with a decrease in available calcium (8,45 %) although soil pH strictly alkaline. In conclusion, the application of 1.5 g humic acid combined with 100 g organic fertilizer effectively enhances agarwood seedling growth and improves degraded soil quality.