Judul: Rekomenasi Pemupukan Kalium pada Budi Daya Cabai Merah Besar (Capsicum annuum L) di Inceptisols Dramaga
Abstrak: The objective of this study is to find out the optimum rate of potassium fertilization in Inceptisols Dramaga. The experiment was conducted at Cikabayan University Farm from March to July 2014. This study was arranged in Randomized Complete Block Design one factor with five K fertilization rates, ie 0X (0 kg K2O ha-1), ¼ X (193.09 kg K2O ha-1), ½ X (386.19 kg K2O ha-1), ¾ X (579.29 kg K2O ha-1), and 1X (772.39 kg K2O ha-1). Potassium fertilizer was applied in three applications at 3, 6, and 9 weeks after transplanting. The results showed that K fertilization increase plant height, leaf number, weight per plant, fruit weight, fruit diameter, fruit length, marketable yield per plot, unmarketable yield per plot, marketable yield per hectare, and unmarketable yield per hectare with linear response pattern. While the addition of potassium did not affect the time of anthesis and fruit ripening. The addition of potassium fertilizer also increase total yield per plot and total yield per hectare with quadratic response pattern. In the medium K soil content with the value of 146.2 ppm (Morgan) K recommendation for red chili in inceptisols Dramaga is 487.5 kg K2O ha-1.
Keyword: Bogor Agricultural University (IPB), optimum rate, Morgan, K2O, fertilizer

Judul: Optimasi Dosis Pemupukan Kalium pada Budi Daya Tomat (Lycopersicon esculentum) di Inceptisol Dramaga
Abstrak: This research objective was to find the optimum rate of potassium fertilizer for specific location of tomato cultivation in inceptisol Dramaga with high soil potassium content (231 ppm). The experiment was conducted at Cikabayan Teaching Farm IPB from July to October 2014. The experiment was arranged in Randomized Completely Block Design with four replications and single treatment factor which was potassium rate in five levels ie 0X (0), ¼X (152.2 kg ha-1), ½X (304.3 kg ha-1), ¾X (456.3 kg ha-1), and X (608.6 kg ha-1). The results showed that on high soil potassium content potassium fertilizer were not affect all of the measured variables, therefore K fertilization is unnecessary.
Keyword: Bogor Agricultural University (IPB), potassium., optimation, nutrient rate, inceptisol

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