Judul: Effect od Slow Release Fertilizer on Nitrogen Availability in Soil and Growth Pineaplle (Ananas comosus L. Merr)
Abstrak: Slow Release Fertilizer (SRF) merupakan salah satu modifikasi pupuk yang bertujuan untuk meningkatkan efisiensi unsur-unsur yang terdapat di dalam pupuk dengan mengatur pelepasannya secara lambat atau bertahap. Kegiatan penelitian dilaksanakan pada bulan September 2021-Maret 2022 di Kabupaten Lampung Tengah, PT Great Giant Food. Kegiatan penelitian bertujuan mengetahui pengaruh pupuk slow release fertilizer terhadap tingkat ketersediaan N dan pertumbuhan tanaman nanas(Ananas comosusL. Merr. ) secara kontinu. Metode yang dilaksanakan selama penelitian, yaitu membuat pupuk slow release fertilizer dengan mencampurkan seluruh unsur mineral (Urea, ZA, K2SO4, KCl, DAP, MgSO4, Kiest G, FeSO4, ZnSO4, Borax, Bifent G) sebagai pupuk standar, kemudian akan dicampurkan dengan masing-masing 3 jenis formulasi pupuk dengan kandungan fly ash dan kompos yang berbeda dan menyelimuti pupuk tersebut dengan bahan polimer sehingga pelepasan pupuk didalam tanah menjadi lambat. Hasil pengamatan ketersediaan N dalam tanah menunjukan perlakuan pupuk belum menyediakan kecukupan hara N dalam tanah untuk kurun waktu 5 bulan. Konsentrasi NO3- dan NH4+ tercuci dipengaruhi oleh lahan yang gundul dan curah hujan. Penguapan NH3 diakibatkan oleh proses evaporasi dan suhu tinggi. Perlakuan pupuk pada pertanaman nanas memberikan dampak positif terhadap sistem pertumbuhan vegetatif tanaman., Slow Release Fertilizer (SRF) is a fertilizer modification that aims to increase the efficiency of the elements contained in fertilizers by regulating their release slowly or gradually. The research activity was carried out in September 2021-March 2022 in Central Lampung Regency, PT Great Giant Food. The aim of the research was to determine the effect of slow release fertilizer on the level of N availability and continuous growth of pineapple ( Ananas comosus L. Merr ) plants. The method carried out during the research was making slow release fertilizer by mixing all elements mineral (ZA, K2SO4, KCl, DAP, MgSO4, Kiest G, FeSO4, ZnSO4, Borax, Bifent G) asa standard fertilizer, then mixed with each other the 3 types of fertilizer formulations with different fly ash and compost contentand covering the fertilizer with polymer material so tthat the release of fertilizer in the soil is slow. The result of observations of the availability of N in the soil showed that the fertilizer treatment had no provided sufficient N nutrients in the soil for a peroid of 5 months. The concentration of leachhed NO3- and NH4+ is affected by demudedland and rainfall. Evaporation of NH3 is coused by the evaporation process and high temperature. Fertilizer treatment on pineapple plantation has a positive impact on the plants vegetative growth system.
Keyword: Evaporation, Vegetative Growth, SRF

Judul: Formulation and Aplication of Slow Release Fertilizer to Support the Initial Phase of Pineapple Plant in PT Great Giant Pineapple
Abstrak: Peningkatan hasil panen pertanian sangat bergantung pada ketersedian hara nitrogen. Hara nitrogen yang sangat umum digunakan yaitu pupuk Urea. Akan tetapi, urea memiliki sifat yang sangat mudah terdekomposisi akibatnya pemupukan menjadi tidak efisien dan memiliki dampak yang buruk terhadap lingkungan. Upaya untuk mengatasi hal tersebut adalah dengan cara merancang pupuk nitrogen yang tidak mudah tercuci. Penelitian ini disusun menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) dengan lima perlakuan dan Setiap perlakuan diulang dalam empat ulangan yaitu perlakuan B0 (Pemupukan standar PT. GGP), B1 (Pupuk standar 6 bulan GGP + 40% fly ash + 20% kompos + polimer spray), B2 (Pupuk standar 6 bulan GGP + 20% fly ash + 40% kompos + polimer spray), B3 (Pupuk standar 6 bulan GGP + 40% fly ash + 20% kompos + campuran polimer + polimer spray), B4 (Pupuk standar 6 bulan GGP + 20% fly ash + 40% kompos + campuran polimer + polimer spray). Penambahan polimer dan fly ash mengurangi ketercucian hara nitrogen pada perlakuan B1, B3 dan B4., Increasing agricultural yields is highly dependent on the availability of nitrogen nutrients. The most commonly used nitrogen nutrient is urea fertilizer. However, urea is very easily decomposed as a result of fertilization being inefficient and even has a bad impact on the environment.The strategies that can be used to overcome this are by designing nitrogen fertilizers that are not easily washed (slow release fertilizer). This study was structured using a Completely Randomized Block Design (RKLT) with five treatments and each treatment was repeated in four replications, namely treatment B0 (standard fertilization PT. GGP), B1 (standard fertilizer for 6 months GGP + 40% fly ash + 20% compost + polymer spray), B2 (Standard fertilizer for 6 months GGP + 20% fly ash + 40% compost + polymer spray), B3 (Standard fertilizer for 6 months GGP + 40% fly ash + 20% compost + polymer mixture + polymer spray), B4 ( Standard fertilizer for 6 months GGP + 20% fly ash + 40% compost + polymer mixture + polymer spray). The addition of polymer and fly ash reduced nitrogen nutrient leaching in treatments B1, B3 and B4.
Keyword: Fly Ash, Nitrogen, Pineapple, Polymer

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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