Judul: Analisis Aplikasi dan Residu Herbisida Pada Pengelolaan Perkebunan Tebu Berdasarkan Aspek Sosioekologis
Abstrak: Nowadays, the agricultural operation that produces maximum output can not be separated from increasing the usage of chemicals such as pesticide. The increasing of herbicide usage would give further concern to environmental polution, which not only affect on non-target organisms but human as well. PT Rajawali II PG Subang sugar plantation is one of the agriculture operation that uses herbicide (one type of pesticide) as weed killer (controller). Some active ingredients of herbicide that used in this company are paraquat, ametryn, 2,4-D, and ammonium glufosinate. This research aims to analyze the level of herbicide residues of paraquat, ametryn, 2,4-D, and ammonium glufosinate in the soil and sugarcane tissue as well as analyzing perception of the employee in herbicide usage and behaviour. Herbicide residues had been analyzed by using High Performance Liquid Chromatography (HPLC). The results showed that the average of employees knowledge on herbicides was up more than 50%, except knowledge of weed resistance (31,81%). The most frequent accident on handling herbicides was wound/skin irritation (77,27%). Personal Protective Equipment (PPE) and other safety rules have been carried out by employees, but the implementation was still inadequate. Commonly PPE used were hat (100%), long sleeve clothes (100%), boots (81,81%), face shields (72,72%), and gloves (22,72%), while eye protection/googles were never used. Meanwhile, content of residual herbicide in sugarcane plantations have a range of the concentration of the residue in the soil of 0,009 - 0,057 ppm for paraquat, 0,018 – 0,16 ppm for ametryn, 0,242 - 2,615 ppm for glufosinate, while 2,4-D was not detected in the soil. The concentration of herbicide residue on the sugarcane was 0,008 - 0,033 ppm for paraquat, 0,023 - 0,058 ppm for ametryn, 0,017 ppm for 2,4-D, and 0,485 - 3,727 ppm for glufosinate. The value of MPL that obtained for the herbicide paraquat was 0,24 mg, ametryn was 0,9 mg, 2,4-D was 18 mg, and glufosinat was 1,2 mg. Maximum amount of sugarcane which can be consumed by adult per day was 7,27 kg for paraquat, 15,52 kg for ametryn, 1058,82 kg for 2,4-D, and 0,32 kg for glufosinate. Glufosinate on sugarcane should be a concern with the amount of sugarcane which is low enough to be consumed by adult until the maximum limit per day 0,32 kg.
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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: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix