Judul: Efektivitas Bakteri Metanotrof dan Ochrobactrum anthropi sebagai Pupuk Hayati dan Pereduksi Emisi Gas CH4 serta N2O di Sawah Anorganik.
Abstrak: Global warming is the increasing of earth's surface temperature which can occurred due to agricultural activities. Agricultural activities contribute to the global warming as sources of CH4 and N2O emissions. Application of methanotrophic bacteria, Ochrobactrum anthropi, Azotobacter and Azospirillum combination could reduce the emission of CH4 and N2O. In addition, these bacteria can fix nitrogen (N2) to enhance the plant growth. The purpose of this study was to determine the effectiveness of methanotrophic bacteria, Ochrobactrum anthropi, Azotobacter and Azospirillum combination as biofertilizer and emission reducer of CH4 and N2O in the inorganic paddy fields. This experiment was arranged by treating 100% dosage of inorganic fertilizer as positive control, 25% dosage of inorganic fertilizer and 25% dosage of inorganic fertilizer mixed by biofertilizer. The observations were made on the growth parameters and the rate of gas fluxes. The combination of bacterial isolates could increase rice growth, grain yield productivity and they also could reduce CH4 and N2O emission.
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Judul: Efektivitas Bakteri Metanotrof dan Bakteri Pereduksi N2O sebagai Pupuk Hayati pada Pertumbuhan Padi di Sawah Organik
Abstrak: Paddy fields are one of the methane (CH4) and nitrous oxide (N2O) emission sources. Methanotrophic bacteria have high activity in the oxidation of methane and denitrification bacteria also have high activity in N2O reduction respectively. Both types of bacteria have ability of fixing nitrogen and controlling emissions of CH4 and N2O from paddy fields. This research was conducted to test the effectivity of methanotrophic bacteria (BGM 1, BGM 5, BGM 9, and SKM 14), two isolates of Ochrobactrum anthropi (BL 1 and BL 2), and Azotobacter sp. and Azospirillum sp. bacteria on the paddy growth in organic rice cultivation. The experimental result showed that paddy growth (Ciherang) which is inoculated by the mixture of four types of bacteria isolates give the better value of growth indicated by some parameters such as number of tillers, plant height, biomass, and total N content than the paddy growth which is given only by compost fertilizer.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular