Judul: Kombinasi antara Pupuk Hayati dan Sumber Nutrisi dalam Memacu Serapan Hara, Pertumbuhan, serta Produktivitas Jagung (Zea mays L.) dan Padi (Oryza sativa L.)
Abstrak: The continues utilization of anorganik fertilizer might result in depletion of soil fertility. The objective of this research was to evaluate the effect of biofertilizer and nutrient sources in improving nutrient uptake, growth and productivity of maize and rice. The experiment was conducted in the plastic house Cikabayan IPB Farm for maize, while for rice it was held in a green house of Balai Besar Biogen Cimanggu, Bogor, West Java. Randomized Block Design was used for experimental design using 2 X 4 factors with 5 replications. The first factor is biofertilizer treatment which consist of application of biofertilizer (H1) and without biofertilizer as control (H0). The second one is the type of nutrient sources that comprise of 4 levels: Soil (N0), Soil + 100 % dosage of anorganik fertilizer (N1), Soil + 100 % dosage of compost (N2), Soil + 50 % dosage of compost + 50 % dosage of anorganic fertilizer (N3). The biofertilizer consist of Azospirillum sp., Pseudomonas sp., and Bacillus sp. selected by the Laboratory of Mikrobiologi, Bogor Agricultural University, Darmaga, Bogor, West Java. Each isolate was enriched in broth medium with the population of 108 cell/ml. The dosage of biofertilizer was 15 ml per pot. The dosage of anorganic fertilizer was 250 kg/ha Urea; 200 kg/ha SP-36, and 200 kg/ha KCl, whereas the compost dosage was 10 ton/ha. The result showed that application of biofertilizer significantly improved nutrient uptake, growth and productivity of rice and maize. For maize, the application of biofertilizer increased macronutrient uptake by 50-97 %, micronutrient uptake by 58,9-63,2 %, dry weight of plant up to 53,7 %, and dry weight of seed up to 36,6 %. For rice, application of biofertilizer resulted in an increase of macronutrient uptake by 10,9-22,5 %, plant dry weight 11,6 %, and total weight of rice seed 7,2 %. The result also showed that the nutrient sources significantly affect the nutrient uptake, growth and productivity of maize and rice. In maize, the highest macronutrient and micronutrien uptake (4,5 g/pot and 10,4 mg/pot respectively) and dry weighy of seed (36,6 g/pot) resulted from the treatment of N2, while the highest dry weight of plant resulted from N3 (6,9 g/pot). For rice, N2 treatment had the maximum macronutrient uptake (2,7 g/pot). The highest micronutrient uptake (5,9 mg/pot), dry weight of plant (41,4 g/pot), and total weight of rice seed (32,8 g/pot) resulted from the treatment of N3. In maize, the N2 treatment in combination with biofertilizer resulted in the highest seed dry weight (41,6 g/pot) and increased productivity by 97-137 % as compared to the treatment of N1 and N3. In rice, the combination treatment of N3 and biofertilizer resulted in the highest weight of rice seed (33,4 g/pot) as compared to the others.
Keyword: 

Judul: Pertumbuhan Vegetatif dan Reproduktif Tanaman Padi dan Jagung pada Berbagai Dosis dan Waktu Aplikasi Pupuk Hayati
Abstrak: The objectives of this research was to find the best dosages and application time of biofertillizer in improving rice (Oryza sativa) and maize (Zea mays) growth and production. This research consisted of two experiments, i.e. dosages and application time experiment. Each experiment was carried out in the green house by Completely Randomize Design with three replications. The dosages experiment consisted of 4 treatments, P0 without biofertillizer, P1-P3 with biofertillizer of 50 g, 100 g, and 150 g per polybag. All the media were prepared using a mixed soil and compost ((5:1) v/v) and anorganic fertillizer of NPK (15:15:15) 8,75 g per polybag. Application time experiment consisted of 3 treatments, H0: 0 day after planting, H1: 4 days after planting, and H2: 14 days after planting. The biofertillizer with the dosages of 150 g per polybag showed the best result indicated by growth and yield parameters. The best time of application was 14 days after planting which indicated by the higher growth parameters and seed yield of rice and maize.
Keyword: 

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
Keyword: