ISOLASI MIKROBA ASLI TANAH ANDISOL DIENG DAN KAJIAN POTENSINYA SEBAGAI INOKULAN PUPUK HAYATI PELARUT FOSFAT

Title : Isolation of Indigenous Phosphate Solubilizing Microbia from Andisols Dieng and Its Potency as Inoculum of Phosphate Solubilizing Biofertilizer. Phosphor (P) is an essential macro nutrient that occur frequently in low availability for plant. This research aimed to find indigenous phosphate solubilizing microbia from Andisols Dieng as biofertilizer inoculum. It was conducted in UNS Soil Biology Laboratory, Faculty of Agriculture, UNS. The research was begun with an exploratory research to obtain P solubilizer isolates (PSB). Research continued by two experiment, set by a completely randomized design (CRD) with two factors: kind of isolate from Andisols Dieng and incubation time. The first experiment was conducted in temporary period in the pikovskaya liquid medium. The second experiment was conducted in vermicompost its carrier. Each treatment combination was repeated 3 times. As much as 106cell or spore was inoculated per gram of medium or vermicompost. Dissolved P , biomass or cell density, and pH at 0,1, 3 and 6 days after incubation for the pikovskaya liquid medium and at 0, 2, 4 weeks for vermicompost. The results showed that there were 4 isolates potential to be inoculums of P solubilizer biofertilizer, they were are isolates of bacteria (P1), Aspergillusniger, Fusarium sp, and Aspergillus tamarii. Aspergillus niger is the most potential inoculums as it highest viability and dissolving phosphate both in liquid media (2.83me/l), and vermicompost (36.78% ).Fosfor (P) merupakan unsur hara makro yang ketersediaannya bagi tanaman seringkali rendah. Penelitian bertujuan untuk menemukan mikrobia asli tanah Andisol Dieng yang berpotensi sebagai inokulan pupuk hayati pelarut fosfat. Percobaan dilakukan di Laboratorium Biologi Tanah, Fakultas Pertanian UNS, Surakarta. Penelitian diawali dengan eksplorasi untuk memperoleh isolat-isolat mikrobia tanah Andisol Dieng, dilanjutkan dengan dua percobaan di laboratorium. Percobaan pertama menggunakan medium cair Pikovskaya dan percobaan kedua menggunakan medium vermikompos. Kedua percobaan disusun dalam rancangan acak lengkap dengan dua faktor yaitu macam isolat mikrobia (empat isolat) dan lama inkubasi (0, 1, 3 dan 6 hari untuk percobaan pertama dan 0, 2 dan 4 minggu untuk percobaan kedua). Masing-masing kombinasi perlakuan diulang tiga kali. Sebanyak 106 sel bakteri atau spora jamur diinokulasikan ke dalam tiap mililiter medium cair Pikovskaya atau tiap gram medium vermikompos.Variabel yang diamati adalah jumlah P-terlarut, kerapatan sel bakteri atau biomassa jamur dan pH medium. Hasil penelitian mendapatkan empat isolat mikrobia yang berpotensi sebagai pelarut fosfat yaitu satu isolat bakteri dan tiga isolat jamur yaitu Aspergillus niger, Fusarium sp dan Aspergillus tamarii. Jamur A. Niger memiliki potensi sebagai inokulan pupuk hayati pelarut fosfat paling tinggi bila dilihat dari kemampuannya berkembangbiak dan melarutkan fosfat dalam medium cair Pikovskaya dan medium vermikompos