Judul: Potensi Oligochitosan, Vitazyme, dan Biofertilizer dalam Meningkatkan Efisiensi Pemupukan, Pertumbuhan, dan Produksi Padi (Oryza sativa L.)
Abstrak: Efficiency of nutrient uptake by rice plants is still low. Various attempts have been made to improve the efficiency of nutrient absorption so that fertilizers are added are not wasted, pollute the environment and save farmers’s expenditures. Oligochitosan, Vitazyme, and Biofertilizer can be an alternative way in order to improve the efficiency of nutrient uptake in rice plants. This study aimed to evaluate the ability of Oligochitosan, Vitazyme, and Biofertilizer in improving fertilization efficiency, growth, and yield of rice plants. This study consisted of pot and field research. The treatments used in pot research were using NPK fertilizer, Oligochitosan Japan, Oligochitosan BATAN, Biofertilizer Azozo and Vitazyme, while field research only used NPK fertilizer, Oligochitosan Japan and Biofertilizer Azozo as treatments. The results showed that pot study at Cihideung Udik Village on 100% NPK treatment, significantly increased the yield of rice compared with 50% NPK. Combinations treatment between 50% NPK fertilizer with Oligochitosan, Vitazyme, and Biofertilizer, significantly increased the yield of rice compared with 50% NPK use only. The yield improvement on these treatment combinations showed that Oligochitosan, Vitazyme, and Biofertilizer were able to increase the efficiency of nutrient uptake by plants more than 100% NPK fertilizer. Oligochitosan and Biofertilizer application on field research in the Cihideung Udik and Situ Gede Village were not significantly different in supporting the growth and production of rice, except on rice panicle length parameter in Situ Gede Village. The growth and production in all treatments at each replication showed the same result. This was apparently due to the lack appropriate of basis fertilizer application on field trials, so that causing the effect on each treatment hard to be evaluated.
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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. ,,,
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular.