Judul: Compost Characteristic Made of Calliandra, Rice Straw, and Vegetable Leftovers
Abstrak: Compost is organic fertilizer which is important for improving physical, chemical and biological characteristics of soil. The function of compost is however depends on the quality of compost. Until now, the quality of compost was valued by C/N ratio and the nutrient content only, without determine humic and fulvic acid content. Organic acid content in compost was hold very important function in improving soil characteristic. In this research, three compost materials, i.e. calliandra, rice straw and vegetable leftovers, with 1 m3 volume each, were composted for six weeks. Based on physical compost characteristic, ripe compost can be taken after six weeks. Changes in temperatures, colour, and smell were observed during the composting. Compost product at each steps of composting was analyzed for nutrients and organic acids content. The result of this research showed that calliandra material produced higher compost’s volume than compost from mixed material, rice straw, and vegetable leftovers. Nutrient content of vegetable leftovers compost was higher than calliandra, mixed material and rice straw compost based on oven-dry (60oC) compost. Qualitative determination of humic acid and fulvic acid can be used as an indicator of compost quality. The highest organic acid content, particularly humic acid was found in rice straw compost and followed by vegetable leftovers, mixed material and calliandra compost that has the lowest humic acid content. Whereas, the highest fulvic acid content was found in calliandra compost and followed by mixed material, rice straw and vegetable leftovers compost. Functional group analysis result in FTIR curve showed changes model and functional group connection that almost similar for each material during composting process, but has different absorbance in composting age., Kompos merupakan pupuk organik yang mempunyai fungsi dan peranan yang penting untuk memperbaiki sifat-sifat fisika, kimia, dan biologi tanah. Fungsi dan peranan kompos pada tanah sangat ditentukan oleh kualitas kompos. Sampai saat ini, penilaian kualitas kompos sering hanya dilihat dari nisbah C/N dan kandungan unsur-unsur hara tanpa memperhitungkan kandungan asam-asam organik khususnya asam humat dan asam fulvat. Jumlah asam-asam organik tersebut memegang peranan sangat besar dalam memperbaiki sifat-sifat tanah. Pada penelitian ini, tiga bahan kompos dari tanaman kaliandra, jerami padi dan sampah sayuran dengan volume masing-masing 1 m3 dikomposkan sampai matang. Berdasarkan sifat-sifat fisik kompos, maka kompos sudah matang setelah dikomposkan selama 6 minggu. Selama proses pengomposan parameter yang diamati adalah perubahan suhu, volume, warna, dan bau kompos. Kompos yang dihasilkan pada setiap tahap pengomposan dianalisis kandungan unsur-unsur hara dan asam-asam organiknya. Hasil penelitian menunjukkan bahwa bahan tanaman kaliandra menghasilkan volume kompos paling tinggi bila dibandingkan kompos dari bahan campuran, jerami padi dan sampah sayuran. Kompos sampah sayuran mengandung unsur hara paling tinggi dibandingkan kompos kaliandra, campuran dan jerami padi berdasarkan bobot kering kompos 60ºC. Penentuan secara kualitatif dari asam humat dan asam fulvat dapat dijadikan sebagai indikator dari kualitas kompos. Kandungan asam-asam organik khususnya asam humat paling tinggi terdapat pada kompos dari bahan jerami padi diikuti oleh kompos sampah sayuran, campuran dan terendah pada bahan tanaman kaliandra. Sedangkan kandungan asam fulvat paling tinggi terdapat pada kompos kaliandra diikuti oleh kompos campuran, jerami padi dan sampah sayuran. Hasil analisis gugus fungsional
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