Judul: The Effectiveness of Combination between Promoting Growth Bacteria, Bradyrlzizobiu11l and Nutrition Sources in Affecting of Soybean Vegetative and Reproductive Growth
Abstrak: In intensive agriculture, continuous application of anorganic fertilizer can decrease soil fertility. The purpose of this research was to evaluate : (1) the effectiveness of combination between Bradyrhizobium and PGPR in influencing nutrient uptake, vegetative growth and yield of soybean in the field, and (2) the effect of biofertilizer in liquid form and solid form in combination with various nutrition sources on growth and production. The experiment was carried out using randomized block design with 3 factors. The first factor was Bradyrhizobium application with 2 levels i.e. without Bradyrhizobium (RO), and with Bradyrhizobium (Rl). The second factor was PGPR application with 3 levels i.e. without PGPR (PO), PGPR in liquid form (PI), and PGPR in solid fonn (P2). The third factor was nutrition sources application with 4 levels i.e. without nutrition sources (NO), with 100% recommendation dosage of NPK fertilizer (Nl), 100% recommendation dosage of compost (N2), and 50% dosage of NPK fertilizer + 50% dosage of compost (N3). Every unit had 3 replications, so that the total experiment were 72 units. The result showed that the application between Bradyrlzizobium in combination with PGPR improved nutrition uptake, plant growth and grain yield of soybean. The higher increase of total macro and micro nutrition uptake was recorded from the combined treatment between Bradyrhizobium and solid PGPR (RIP2) which an increase by about 66,20%, and 41,40%, followed by combination between Bradyrhizobium and liquid PGPR (RIPl) by 39,17% and 16,20% as compared to the control. The combination RIP2 increased number of branches, plant dry weight, root dry weight, number of nodule, dry weight of nodule, number of pod, and seed dry weight/plant by approximately 31,33%, 50,87%, 48,17%, 207,68%, 185.66%, 78,7%, 83,69%, respectively compared to the control. The best treatment was resulted by RIP2N2, the combination between Bradyrhizobium, solid PGPR and compost 100% dosage. This treatment had the significant in increasing the number of branches, fresh weight, plant dry weight and root dry weight by 101,64%, 159,30%, 118,42%, 115,36% respectively. This treatment also caused the improvement of number of pod, and seed dry weight/plant by 163,64% and 174,73%. These result showed that the biofertilizer produced from PGPR have synergical effect with Bradyrhizobium to improve nutrient absorption, growth and yield of soybean.
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Judul: Addition of Plant Growth Promoting Rhizobacteria to Improve the Quality of Organic Fertilizer, Nutrient Uptake, Growth and Yield of Upland Rice and Maize
Abstrak: Biofertilizer is one of the alternative fertilizers that can increase nutrient uptake, plant growth and production. The purpose of this research was to evaluate the quality of organic fertilizer (compost) enriched with bofertilizer and its effect on nutrient uptake, growth and yield of upland rice and maize. This experiment was conducted using a Randomized Block Design with two factors of treatment. The first factor was organic fertilizer that consist of three levels: compost without biofertilizer as a control, compost enriched with biofertilizer, compost and biofertilizer applied separately on the day of planting. The second factor was the anorganic fertilizer consisting 2 levels: 50% and 100% of recommended doses. The upland rice var Situbagendit and maize var Bisma were grown on the field condition. The bacteria used as biofertilizer were Bacillus subtilis strain HU48, Pseudomonas beteli strain ATCC1986IT, Azotobacter sp. strain HY1141, dan Azospirillum sp. strain NS01. The compost enriched with biofertilizer had the best effect on most variables observed including nutriet uptake, growth, biomass, and production of both crops. This enriched compost increased macro and micro elements uptake of upland rice and maize. This treatment increased the production of upland rice up to 73% while the maize production increased up to 38%. Anorganic fertilizer increased significantly the macro nutrient uptake in upland rice but not in maize. In comparison with 50% dose of anorganic fertilizer, 100% dose anorganic fertilizer increased the plant growth and yield of upland rice and maize. However, this increase was not significant. The best treatment was showed by compost enriched with biofertilizer that was combined with 100% anorganic fertilizer. This treatment increased grain weight up to 109,28% of upland rice, and seed weight up to 41,18% of maize compared to control.
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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.