Judul: Pupuk hayati Azotobacter dan mikrob pelarut fosfat untuk meningkatkan pertumbuhan jagung (Zea mays L.) pada ultisol darmaga
Abstrak: Many efforts had been doing to increase the production of agricultural . One of them was uing the prime variety followed by increased of chemical fertilizer. Utilization of biofertilizer that contained by Azotobacter and Phosphate Solubilizing Microbe were giving more advantages for the users. Except could be increase the readiness of N and P in soils, using Azotobacter and Phosphate Sohbilizing hficrobe inoculants can also reduce the production cost as well as reduced the environmental pollution. The aim of this research was to selected the effective of Azotobacter and Phosphate Solubilizing Microbe which able to improve the growth of maize also uptake nutrition N and P of Ultisols Darmaga. It was isolated from estate palm oil soils of PT. Mitra Ogan and Tea Plantation of PT. Mitra Kerinci, Sumatera Barat. Maize seeds Pionner-12, Ultisols Darmaga, chemical ferlitizer (Urea 41.09 % N, SP-36 16.47 %J P2Os and KC1 50.61 % K2O) were used in this rcsearch.
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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.
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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