Judul: Dampak Aplikasi Herbisida Sodium Bispiribak pada (Bispyribac sodium) Tanaman Padi Sawah terhadap Residunya dalam Tanah dan Tanaman Padi (Jerami dan Beras)
Abstrak: Herbicides are agricultural chemicals used to control weeds or to inhibit plant growth normally. The use of chemicals is considered much more efficient, cheaper and faster because it saves labors. Weeds are wild plants that can be reduce the rice yield if not controlled effectively. The cost of weed control in rice plant reaches 50% of total production cost. This study purposed to analyze herbicide residue in soil, straw and yield (rice), and to analyze economic comparison of rice cultivation with and without the use of herbicides. Data are obtained from the result of research conducted in the rice planting field at Cijujung Village, Cibungbulang District, Bogor and at Agrochemical Materials Residue Laboratory, Agricultural Environment Research Center, Bogor. The result of this study shows that based on analysis of Bispyribac sodium herbicide residue in three samples, that are soil, straw and yield (rice), the highest herbicide concentration is found in straw sample. The Maximum Residue Limit of Bispyribac sodium herbicide is 2 ppm, the concentration of herbicide residue in rice samples are still below the Maximum Residue Limit and still within safe limit to consume. Based on the analysis of farming, comparative cost analysis for rice cultivation with Bispyribac sodium 0.5 l/ha treatment give more effective influence and more profitable for both energy and economically than rice cultivation with manual treatment.
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Judul: Dampak Aplikasi Herbisida IPA Glifosat pada Pertanaman Padi Sawah Sistem TOT terhadap Tanah dan Tanaman Padi
Abstrak: Weeds are among factors in decreasing paddy production, therefore should be controlled. The effects of weeds in decreasing paddy ranging from 6-87%. Weed control is generally carried out chemically by using herbicides. The use of herbicide with active subtance glyphosate is very common in agricultural areas in the world. This herbicide is used for post-emergence of weeds and it is non-selective. Using herbicides to control weeds is more efficient, inexpensive, and faster. In fact, it is more practical and cost-saving because there is no need to hire many laborers to remove unwanted plants. Application of no-tillage technology (TOT) using herbicides is considered far more effective and efficient. However, continuous use of herbicides can result in residues in the soil, plants and harvest results. The objective of this study was to analyze the influence of TOT and its combination with Glyphosate IPA herbicide on paddy production and its economic value, and the concentration of the residues of Glyphosate IPA herbicide in soil, straw and rice, and the maximum residue limit. This research was carried out in the paddy field with a plot size of 3 by 3 m as many as 5 treatment plots with 3 replications in order to total 15 experimental plots. The tillage was not performed on the experimental plots, except on the 3 plots with Gm treatment where conventional tillage (OTS) as farmer habits in the field. The spraying of herbicide was done once before paddy planting by using herbicide with active glyphosate IPA on perfect tillage treatment (Gm), G0 (without herbicide, control), with a glyphosate dose of 1.5 l ha-1 (G1), 3 l ha-1 (G2) and 4.5 l ha-1 (G3). Application of herbicides was carried out by spraying on treatment plots, except the control plot, with the right dose which had been determined. Seeds were evenly spread using paddy seeds of Mekongga variety. The seedbed was adapted to the common treatment carried out by farmers. The seedlings are ready for planting at aged 25 days. The planting method was carried out by placing the seedling in a digged-hole (ditugal). The planting on conventional tillage (OTS) was performed as usual, without ditugal. Fertilization was done twice using urea fertilizer as much as 200 kg ha-1, SP36 100 kg ha-1 and NPK Phonska 100 kg ha-1. Chemical fertilization was done by distributing it evenly on paddy plants. Weeding was carried out 2 times on the plots of Gm treatment, that is, when the paddy was 30 days and 60 days after seedling planting. Harvesting was done at the age of ± 4 months in which ready-to-harvest paddy was yellow and the branches already bent. Harvesting was done on the sample plots observed by covering each plot with tiles measuring 1 m by 1 m. Harvesting on the sample plots was carried out with caution. The paddy grain samples of each treatment were taken and weighed. The straw and soil samples of each treatment were taken from the tiled plots. Herbicide residue tests were carried out on the three types of samples: soil, straw and rice (milled paddy). The sampling of
Keyword: Glyphosate herbicide, maximum residue limits, paddy, weed control

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