Judul: Pertumbuhan dan Potensi Produksi Tanaman Padi dan Jagung Pada Tanah Podsolik Merah Kuning yang Diperkaya Pupuk Hayati
Abstrak: Yellow Red Podzolic soil (YRP) is one of the low fertility soil. The fertility of YRP soil could be increased using the biofertilizer because it can improve soil fertility, plant growth and yield. The objective of this study were to analyze the growth of plant and production potential of rice and maize on YRP soil, which enriched by biofertilizer. The biofertilizer used in this research were Plant Growth Promoting Rhizobacteria (PGPR) (Azotobacter sp., Azospirillum sp., Bacillus subtilis and Pseudomonas beteli), arbuscular mycorrihzal fungus (AMF) that was Glomus manihotis, endophytic that was Aspergillus niger, and an anorganic fertilizer used NPK Pelangi. The experiment used Complete Randomized Design with ten levels of treatment for rice and thirteen levels of treatment for maize, all in five replication. Rice cultivated on a pot which filled by 8 kg of soil. Maize cultivated on a poliybag (40 cm x 40 cm) filled by 10 kg of soil. The result showed that the aplication of biofertilizer (PGPR + endophytic) with reduced NPK up to 50% was not different than control (NPK 100% + compost without PGPR) to support plant growth and yield of rice. While maize showed that the aplication of biofertilizer (PGPR + endophytic + AMF) with reduced NPK up to 50% showed significantly increase height of plant, round of stem and length of ear than control (NPK 100% + compost without PGPR). This research suggest that enriched of podzol soil with biofertilizer could reduce application of anorganic fertilizer (NPK) up to 50% of recomendation doses.
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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: 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