Judul: Increasing the growth of mangosteen (Garcinia mangostana) seedlings with growing media optimation
Abstrak: Mangosteen is slowly growth trees that caused by root system development. Mangosteen root system has limited number of lateral roots and easily disturbed by unfavorable medium environmental conditions such as poor aeration, water availability, and nutrient content. The objective of this study was to enhance the growth of mangosteen seedlings by modifying media properties. The experiment was conducted in the Plastic house at Centre for Tropical Fruit Studies (CETROFS) Bogor Agricultural University, Tajur from January 2009 until May 2011. The study consisted of five experiments. The first experiment conducted to study the morphological and physiological characteristics of mangosteen seedlings that cultivate in drought conditions. Experiment arranged in a completely randomized block design with three replications. The results shown that an increasing the level of drought stress was decreased canopy and root growth include plant height, leaf area, root length, shoot and root dry weight and also root volume. Increasing the level of drought stress also led to significantly increased proline content. The second experiment was conducted to obtain the porosity of the media from various sources. The result shown that the lowest porosity in media was 53.48% and the highest was 69.63%, thus this research obtained four porosity ranges e.i.: 51-55%, 56-60%, 61-65% and 66-70%. These criteria then applied as the basis of the experimental treatments for the third study. The third experiment was conducted to analyses the growth of mangosteen seedlings at different water availability and porosity of the media. The result shown that watering intervals 6 day + water retaining polymer (WRP) at 61-65% porosity media drive the availability of optimal water and air. It caused an optimal rate of photosynthesis, stomata conductivity and the highest water potential of leaf tissue. The fourth experiment was conducted to study the growth of mangosteen seedlings at different method of fertilizer application and porosity of the media. The result shown that fertilizer application by fertigation in 61-65% porosity media produced the highest growth of root length, root dry weight, shoot dry weight and total dry weight. Nutrient uptake of N in the leaf by fertigation applications was support shoot and root growth higher than the application of granular fertilizers and slow release fertilizer. The fifth experiment was conducted to study mangosteen plant growth in two types of pots containers in various media porosity. Results shown that the use of woven bamboo pots obtained shoot and root growth higher than the polybag. As the results from previous experiments, the porosity of 61-65% seems to consistently produce the highest shoot and root growth.
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Judul: Pengaruh komposisi media dan jenis pupuk terhadap pertumbuhan bibit mangga Mangifera indica L.
Abstrak: Percobaan ini bertujuan untuk mengetahui komposisi media dan jenis pupuk yang dapat meningkatkan pertumbuhan bibit mangga. Hipotesis yang diajukan adalah: 1. Terdapat perbedaan pertumbuhan bibit mangga pada komposisi media dan jenis pupuk yang berbeda 2. Terdapat interaksi antara komposisi media dengan jenis pupuk yang memberikan respon paling baik dalam menunjang pertumbuhan bibit mangga. Percobaan ini dilakukan di Agropromo Center, Departemen Budidaya Pertanian pada bulan November 2003 sampai Februari 2004. Bahan tanaman yang digunakan adalah bibit tanaman mangga kultivar Manalagi hasil okulasi berumur 1 tahun, bibit tersebut ditanam dalam polibag yang berukuran 30 cm x 35 cm. Percobaan menggunakan Rancangan Acak Kelompok 2 faktor. Faktor pertama adalah komposisi media yaitu: (M1) arang sekam:tanah:pukan (3:2:1). (M2) pasir:tanah:pukan (3:2:1), (M3) kokopit:tanah:pukan. Faktor kedua adalah jenis pupuk yaitu: (P1) NPK 15-15-15 5 g, (P2) Dekastar 22-8-4 1.7 g + NPK 15-15-15 2.5 g, (P3) Supercote 17-17-17 2.2 g + NPK 15-15-15 2.5 g. Setiap percobaan diulang sebanyak lima kali, sehingga didapatkan 45 satuan percobaan. Peubah yang diamati meliputi tinggi tanaman, diameter batang atas dan batang bawah, jumlah tunas, jumlah cabang, panjang tunas, luas daun dan volume akar. Hasil penelitian menunjukkan bahwa faktor tunggal komposisi media secara umum berpengaruh nyata terhadap peubah tinggi tanaman. diameter batang atas, diameter batang bawah, jumlah tunas dan jumlah cabang. Komposisi media M3 (kokopit:tanah:pukan) mampu meningkatkan tinggi tanaman, diameter batang atas dan diameter batang bawah. Sedangkan media M2 (pasir:tanah:pukan) meningkatkan pertumbuhan jumlah tunas dan jumlah cabang. Pengaruh faktor tunggal penggunaan jenis pupuk menunjukkan bahwa pupuk P2 (Dekastar 22-8-4 1.7 g + NPK 15-15-15 2.5 g) dan P3 (Supercote 17- 17-17 2.2 g + NPK 15-15-15 2.5 g) mampu memberikan pengaruh yang nyata terhadap peubah tinggi tanaman, panjang tanas, dan diameter batang bawah. Tetapi jenis pupuk P2 (Dekastar 22-8-4 1.7 g + NPK 15-15-15 2.5 g) memberikan pengaruh yang lebih baik dibandingkan pupuk P3 (Supercote 17-17- 17 2.2 g + NPK 15-15-15 2.5 g). Interaksi antara komposisi media dan jenis pupuk menunjukkan perbedaan yang nyata pada kombinasi perlakuan media M2P1 yaitu pasir:tanah:pukan (3:2:1) dengan jenis pupuk NPK 15-15-15 5 g karena mampu meningkatkan jundan cabang pada 13 dan 14 MST. ...
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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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