Judul: Determination of N, P, and K Fertilizer Optimum Rates for Bambara Groundnut (Vigna subterranea [L.] Verdcourt).
Abstrak: Bambara groundnut is the one of nuts that have a high potential to be developed. Bambara groundnut has the best drought resistance among other nuts, but it also has another advantage that is tolerant of unfertile soils. The average yield of dry pod weight from agricultural fields in Indonesia were under 4 ton ha-1, that value is still low. Therefore, must be an efforts to improve Bambara groundnut production. Fertilization is the key efforts for increased the productivity of Bambara groundnut. The objective of the research was to determine optimum rate of N, P, and K fertilizer for Bambara groundnut (Vigna subterranea [L.] Verdcourt) production. Three experiments were conducted at Cikarawang Farm, Dramaga, Bogor from March to July 2013. Each experiment tested different rates of N or P or K fertilizer with randomized compeletely block design and three replications. The fertilizer rates were 0, 50, 100, 150, and 200% of reference rate (100% N = 45 kg N ha-1, 100% P = 54 kg P2O5 ha-1, 100% K = 45 kg K2O ha-1). On all experiments, 100% P, 100% K, and 30% N were applied at planting, while 70% N was applied at 5 week after planting. Plot size was 6 m x 3 m, with plant spacing of 60 cm x 30 cm. Harvesting were conducted at 16 week after planting. The result showed that leaf P content increased linearly with N fertilizer application. Leaf N content decreased linearly with P fertilizer application. Root fresh weight, seed N content, and shoot dry weight quadratically increased with K fertilizer application. Because of very limited numbers of variable that were significantly affected by the treatment, optimum rate of N, P, K fertilization can not be determined through multi nutrient response technique in these experiments. Only the optimum rate of K fertilizer that can be determined with the range of 51.48-69.78 kg K2O ha-1. Based on production, the highest productivity estimation were 30.91 kg N ha-1, 54.81 kg P2O5 ha-1, and 46.85 kg K2O ha-1 although not significant.
Keyword: multi nutrient response, NPK fertilization

Judul: Pengaruh Perlakuan Invigorasi Pada Benih Yang Berbeda Tingkat Masak Terhadap Viabilitas Dan Vigor Benih, Pertumbuhan Tanaman, Dan Hasil Kacang Bogor (Vigna subterranea (L.) Verdcourt)
Abstrak: Bambara groundnut can be cultivated in marginal land, however, its productivity is low. In order to increase the productivity, high quality of seeds must be used. Two consecutive experiments were conducted in laboratory and field at Bogor Agricultural University from April to October 2010. Seeds of three maturity levels were harvested from farmer’s field in Sukabumi, April 2010. The seeds were dried down to 11.6% moisture content before being used. The objectives of the experiments were to evaluate effects of seed invigoration applied on bambara groundnut seeds of three maturity levels on seed vigor, plant growth, and yield. Laboratory experiment was arranged in a completely randomized design while field experiment was arranged in a completely randomized block design. In both experiments, two factors were applied, seed maturity and invigoration. There were three levels of seed maturity i.e. seeds harvested at 119, 122, and 125 days after planting (dap). Seed invigoration consisted of untreated, Rhizobium sp., matriconditioning, matriconditioning plus Rhizobium sp. Matriconditioning was conducted using ratio of seeds to carrier (burned rice hull) to water of 20:12:12 (g) for 3 days in air-conditioned room ca. 25 0C. Rhizobium sp. 0.3 g/100 g seeds was either applied on seeds just before planted or incorporated in matriconditioning. Results of the laboratory experiment showed that matriconditioning alone or matriconditioning plus Rhizobium sp. applied on seeds harvested at 122 daf or 125 dap improved seed vigor (speed of germination and index of vigor). However, there was no interaction occurred between the two factors in the field experiment. Seeds treated with matriconditioning plus Rhizobium sp. or harvested at 125 dap showed the best improvement in plant growth (plant height, number of leaves, number of branches) and yields (number and weight of pods).
Keyword: 

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology