Judul: Pengaruh Kaptan, Trass, Dan Pupuk Fosfor Terhadap Kedelai Varietas Orba Pada Podsolik Jasinga
Abstrak: Soybean is one of commodities that is consumed in large quantities by Indonesian peoples. In the year of 2009, total of soybean was needed by Indonesian about 2.2 million tons. At that time the local soybean production was about 974,512 tons, so that the lack of soybean production should be added by imports. One of the main problems of low soybean yield in Indonesia is low of soil fertility. Additional of ameliorant matter such as agricultural lime and Trass, and fertilization are the way to solve the problem of soil fertility. In this case, agricultural lime and Trass act as liming matterial, and Trass also potentially as a source of silicate nutrient for plants. The objectives of this study to know the influence of agricultural lime, Trass and phosphorus fertilizers on soil chemical properties and the growth, nutrient uptake, and yield of soybean in Jasinga’s Podzolic. The experiment was conducted at the Cikabayan Experimental Station and analysis of soil and plant tissue in Soil Chemistry and Fertility Laboratory, Faculty of Agriculture, Bogor Agricultural University. This experiment was conducted in a Completely Randomized Design (CRD) with two factors, the first factor was dosages of ameliorant matter (agricultural lime/Trass) (without amelioran, 1x exch-Al, 2 x exch-Al) and the second factor was dosages of phosphorus fertilizer (without P, 250 kg / ha, 500 kg / ha), and each treatment was replicated three times. The results of the study showed that agricultural lime treatment increased soil pH and decreased exch-Al; while Trass treatment was not significantly affect on pH and exch-Al. Agricultural lime, Trass and P fertilizer treatments increased available soil P. The available P and exchangeable Ca of soil with the treatment of agricultural lime was higher than treatment of Trass. In both ameliorant experiment, P fertilizer treatment significantly increased plant height and leaf number, but in agricultural lime treatment, the increase of plant height and leaf number greater than Trass treatment. Agricultural lime treatment significantly affected the leaf number, whereas Trass was not. All treatments did not significantly affect the fresh and dry weight of stover. While, phosphorus fertilizer treatment significantly increased the fresh and dry weight of roots in Trass experiment . Phosphorus treatment significantly increased of P uptake of soybean in both ameliorant wether agricultural lime or Trass. Agricultural lime treatment significantly increased the Ca uptake of soybeans, while was not for Trass treatment. Trass treatment increased uptake of SiO2, while agricultural lime was relatively small. Increasing dosage of agricultural lime significantly increased the weight of pods and seeds, but Trass dosages was not affected. The average weight of pods and seeds of soybeans on agricultural lime experiment was higher than Trass experiment.
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Judul: Pengaruh Trass dan Pupuk Fosfor terhadap Pertumbuhan dan Produksi Padi Gogo serta Perubahan Sifat Kimia pada Latosol Gunung Sindur
Abstrak: The high conversion of rice fields to non-agricultural fields have reduced rice production, so it needs the utilization of dry land for paddy cultivation. Latosol is one type of nutrient-poor soils, especially Silica (Si) and phosphorus (P), and generally it is acidic due to further weathering and intensive leaching. This study aimed to determine the effect of Trass and Phosphorus (P) on yield and nutrient uptake of rice plants, as well as changes in the chemical properties of Mount Sindur’s Latosol. This study was a greenhouse experiment conducted in Cikabayan University Farm, Bogor Agricultural University. Soil and plant analysis carried out in the Laboratory of Chemistry and Soil Fertility, Department of Soil Science and Land Resources, Faculty of Agriculture, Bogor Agricultural University. This study took place from October 2012 to April 2013. This experiment used a completely randomized design (CRD) with 2 factors. As the first factor was Trass doses (0 tonnes / ha (T0), 2.37 tonnes / ha (T1), 4.74 tonnes / ha (T2), and 7.11 tons / ha (T3). Second factor was P fertilizer (0 ppm P (P0), 50 ppm P (P1), and 100 ppm (P2). Experiment was repeated 3 times so that there were 36 experimental units. Results showed that there was no interaction effect between Trass and phosphorus in all observed variables. But as a single factor, Trass significantly affect to increase the number of productive tillers in treatment T3 equal to 17.5%, while the increasing amount of soil available-P influence T1, T2, and T3 treatments, respectively for 25%, 62.5, and 149.4%. Further, there was an increase in P-uptake effect on T1, T2, and T3 treatments, respectively for 4.5%, 9.5%, and 24.3%. Moreover, P Fertilizer application was significantly affect the increasing of plant height on P1 and P2 treatments, respectively for 17:45% and 17.6%, number of tillers earnings 3.8% and 20%, biomass weight for 108.4% and 159.7%, and the grain weight for 47.9% and 52.1%, while the increase effect on Si-uptake of P1 and P2 treatments, respectively for 62.07% and 87 %, and decrease the available-Si, respectively for 9.1% and 22.5%.
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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