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: Analisis efektivitas pengendalian gulma secara mekanis, kimia dan kombinasi pada kebun tebu rakyat di Cimahpar, Bogor
Abstrak: This research aims to study any weed control methods on sugarcane plantation, was conducted on sugarcane plantation in Cimahpar, North Bogor – Bogor from May to August 2010. The experimental used ten levels of weed control treatments and two replications. The treatments were Ko = without weed control, M = mechanical, MM = mechanical – mechanical, MMM = mechanical –mechanical - mechanical MK = mechanical – chemical, MMK = mechanical – mechanical – chemical, MKM = mechanical – chemical – mechanical, K = chemical, KM = chemical – mechanical and KMM = chemical – mechanical – mechanical. Controlling method chemically used two varies herbicide, gliphosate and paraquat, while controlling method mechanically was conducted by using walking type cultivator. Glyphosate herbicide has been used on sugarcane area dominated by Imperata cylindrica and paraquat herbicide has been used on sugarcane area dominated by grass or Paspalum conjugatum. The result showed that the treatment of MMK could suppress the growth of weeds, especially Imperata cylindrica is the best in the percentage of weeds by 0.75% and 1.505 cm high weeds on domination Imperata cylindrica areas. MKM treatment showed suppression of growth of weeds, especially Paspalum conjugatum of the best weed in the percentage of weeds 9% and 4.39 cm high weeds on sugarcane Paspalum conjugatum areas. Paraquat herbicide usage caused poisoning symptoms in sugarcane with exist of color change on sugarcane stem, further symptoms was not causing death.
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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