Judul: Formulasi Konsorsium Rizobakteria Pelarut Fosfat dengan Bradyrhizobium japonicum sebagai Pupuk Hayati dan Aplikasinya pada Tanaman Kedelai
Abstrak: Phosphate solubilizing rhizobacteria were known for their ability to convert insoluble form of phosphate to the accessible form. The use of rhizobacteria as biofertilizer is one of the most promising biotechnologies to improve plant production. This study was conducted to formulate phosphate solubilizing rhizobacteria (Bacillus sp. Cr and Pseudomonas sp. Crb) coinoculated with Bradyrhizobium japonicum (Bj) and appliance them to soybean plant as biofertilizer. Pikovskaya medium containing tri-calcium phosphate at concentration of 0.5% was used to measure P-solubilizing ability of tested strains. Results revealed that Crb1 is the most powerful P-solublizer using tricalcium phosphate as a P source. It was also observed decreasing in pH along with the increasing of amount of soluble P ranged from -0.96 to -0.42 from initial culture during 72 hours. Isolates of the rhizobacteria (Crb and Cr) were grown in media containing skim milk and molases prior to formulation in peat as a carrier material. The combination of three strains produced 4 packages of inoculants. Each packages was tested for their viability and effectiveness on soybeans in the field. The number of bacterial population after 9 months of storage ranged from 7.5 x 106 to 5.8 x 108 cfu gr-1 of peats. Field experiment showed that treatments designed as F1+NPK and F3+NPK were significantly increased soybean plant growth and mineral uptake compared to untreated control and better than NPK treatment. While F1+NPK and F2+NPK were able to increase soybean productivity.
Keyword: 

Judul: Teknologi Formulasi Inokulan Rhizobakteria Pemacu Tumbuh dan Aplikasinya pada Tanaman Kedelai
Abstrak: Soybean production in Indonesia is being increased to fulfill national requirement. One of the solution that have been known is use biofertilizer as substitute of chemical fertilizer. Based on previous study, three strains of Pseudomonas sp. (Crb 3, Crb 17, Crb 68) and Bacillus sp. (Cr 24, Cr 44, Cr 66) were potential as plant growth promoter and biocontrol of root phytopathogenic fungi. In addition, Bradyrhizobium japonicum 11 was potential as a nitrogen fixation bacteria of soybean plants. The aims of this study are to formulate plant growth promoting rhizobacteria biofertilizers and to applicate biofertilizers on soybean plants. Those bacteria were formulated with carrier material such as peatsoil, zeolit, and kaolinit. The result of formulation was three forms of biofertilizers i.e. talc, powder, and granule. Then, those biofertilizers were applicated on soybean plants in green house. Based on statistical test result, N-Fo (S) III could enhance plant height and dry weight compared to control in sterile condition. In non-sterile condition, N-Rs (G) III and NRs (T) III could enhance four parameters of plant growth compared to control significantly. The increase of plant growth were more significant in non-sterile condition than in sterile condition.
Keyword: 

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf