Pengaruh abu terbang dan bahan humat terhadap pertumbuhan tanaman sengon (Paraserienthes falcataria) dan sifat-sifat kimia tanah di lahan bekas tambang batubara

Abstract

Indonesia is the largest coal producer in Southeast Asia. Some problems will appear in coal mining during and after mining especially land degradation. For reclaiming land degradation, some efforts can be done to improve the physical, chemical, and biological properties of soil. Some of the alternatives for soil ameliorant are fly ash and humic substances. Fly ash can be obtained from the coal burning at the electric power plant while humic substances can be extracted from organic materials. Application of fly ash and humic substances in the soil at ex-coal mining are expected to improve the physical, chemical and biological properties of soil. The research aims to find out the effect of fly ash and humic substances on sengon’s growth (Paraserienthes falcataria) and chemical properties of soil in the ex-coal mining land. This research was conducted in a greenhouse, nursery PT. Kaltim Prima Coal, East Kutai, East Kalimantan Province. The research used a completely randomized design factorial of two factors. The first factor were 3 levels of fly ash: 0 tons/ha, 40 tons/ha, and 80 tons/ha, or equivalent to 0 g/polybags, 200 g/polybag, and 400 g/polybag. The second factor were 3 levels of humic substances: 0 l/ha, 15 l/ha, and 30 l/ha, or equivalent to 0 ml/polybags, 0,075 ml/polybags, and 0,15 ml/polybags. Each polybag filled with soil material as much as 10 kg. Each treatment was repeated as many as 5 times. The results showed the interaction between fly ash and humic substances significantly increased the N content, N absorption, plant height, and weight of leaves. The highest result of those parameters was the treatments of F2H2. The analysis also showed that fly ash significantly increased pH, total-N, organic-C, exchangeable-K, exchangeable-Na, exchangeable-Ca, base saturation, K content, Mg content and Mg uptake of leaves, and tended to increase the available-P, P content and P uptake of leaves, and decreased the exchangeable-Al. Humic substances significantly increased the available-P and exchangeable-Ca, and tended to increase pH, C-organic, Cation Exchange Capacity (CEC), Mg uptake of leaves, and decreased the exchangeable-Al.