Effectiveness of fulvic acid to the growth of Swietenia macrophylla King. with addition phosphate at post mining land in Indonesia

Abstract

Mining activities would cause a decrease in carrying capacity and land function due to erosion, changes in soil structure, loss of vegetation, pollution, nutrient depletion and increasing Al³⁺ levels so that soil pH conditions will be low. This study aims to increase the Swietenia macrophylla King growth response at the gold mining land that can be used as a tool for consideration in revegetation activities. The design used in this experiment was a complete randomized design (CRD) factorial with 2 factors. The first factor was the application of fulvic acid (F₀ = control, F₁ = concentration of 2% (2 ml of fulvic acid plus 98 ml of water), F₂ = 3% (3 ml of fulvic acid plus 97 ml of water), F₃ = 5 % (5 ml of fulvic acid plus 95 ml of water) and the second factor was the application of phosphate fertilizer (P₀ = 0 g / polybag, P₁ = 10 g / polybag, P₂ = 15 g / polybag and P₃ = 20 g / polybag) were used for preparation of different treatments. The treatment of fulvic acid significantly affected the growth of S. macrophylla for parameters of diameter, total dry weight, and root dry weight of S. macrophylla. The single effect of phosphate fertilizer treatment had a significant effect on high growth, diametert, total wet weight, and total dry weight of S. macrophylla. The interaction of fulvic acid and phosphate fertilizer significantly affected the diameter, total dry weight and root dry weight of S. macrophylla. F₂P₃ treatment (3% fulvic acid and 20 g phosphate fertilizer is the best combination treatment. Therefore, application of fulvic acid and phosphate fertilizer on post mining soil improves soil fertility and decreases Al elements which are toxic to plants.