Pemanfaatan arang aktif sebagai carrier unsur hara mikro dalam pembuatan pupuk lambat tersedia

Abstract

In many plantations, fertilizers were often added in high dosage and applied several times in order to get maximum productivity. Actually, some processes in soil caused not all nutrients in fertilizer could be uptaken by plants. Besides, high dosage can be toxic to plants. The use of slow release fertilizer can overcome this case. Slow release fertilizers (SRF) were fertilizers coated within a substance that enables a slow release time and had higher efficiency rate than soluble fertilizers. This research was aimed to: 1) identify the characteristics of bamboo and coconut shell activated charcoal that were activated in 600oC or 700oC temperature and steamed for 90 minutes, 2) obtain the data of adsorptive capacity of activated charcoal to the nutrients mixed, 3) gathering the information about nutrients release rate of fertilizer produced, and 4) determine the influence of slow release fertilizer addition to nutrient uptake in Acacia crassicarpa. The study was conducted by converting materials into charcoal. The charcoal was then activated in 600oC and 700oC temperature and steamed for 90 minutes. The activated charcoal was ground and analyzed based on SNI 06-3730-1995. SRF was formulated by soaking fine activated charcoal in 1N or 2N of CuSO4, FeSO4 or ZnSO4 solution for 24 hours. Analysis conducted were observation of surface topography by SEM, qualitative analysis using EDX, calculation of chrystallinity, width, length and number of aromatic layer, and determination of total Cu, Fe and Zn in SRF. The optimal treatment was chosen to determine its release rate by extracting fertilizer with distilled water and 2% citric acid during 0, 15, 30, 45, and 60 minutes. The influence of SRF addition to nutrients uptake was determined by observing nutrients content in root. The results showed that the activated charcoal produced met SNI 06-3730-1995 except for its adsorptive capacity to iodine and blue methylene. Nevertheless, the activated charcoal could be used to adsorb nutrients mixed as shown by SEM and EDX results. The adsorption of Cu, Fe and Zn increased the activated charcoal chrystallinity and influence its width and length of aromatic layer. The highest nutrients concentration obtained were 11,443 ppm Cu, 5,476 ppm Fe, and 6,603 ppm Zn for bamboo activated charcoal and 10,775 ppm Cu, 7,611 ppm Fe, and 6,343 ppm Zn for coconut shell activated charcoal. Nutrients in the charcoal could be released slowly and could not be easily leached out.