Judul: The Effect Of Four Types Of Urea Fertilizer on Biomass and Nitorgen Uptake in Paddy (Oryza sativa L.)
Abstrak: Padi merupakan tanaman yang penting di Indonesia karena padi menjadi bahan makanan pokok bagi sebagian besar masyarakat Indonesia. Peningkatan produksi padi membutuhkan pemupukan yang relatif berkesinambungan sehingga aspek efisiensi menjadi penting. Nitrogen (N) merupakan unsur hara makro yang penting untuk padi. Kehilangan hara terutama hara N, adalah masalah yang sering terjadi dan menyebabkan kesuburan tanah rendah. Studi ini bertujuan mengevaluasi pengaruh jenis pupuk urea pada bobot kering biomasa, serapan N dan efisiensi serapan N pada tanaman padi. Penelitian ini disusun dalam rancangan acak lengkap dengan faktor tunggal yaitu jenis pupuk urea. Perlakuan terdiri dari lima perlakuan yaitu urea konvensional Kujang, urea konvensional Pusri, urea slow release Granul dan urea slow release Prill dan kontrol tanpa aplikasi pupuk. Perlakuan diulang empat kali. Sampel tanaman dikumpulkan setiap minggu dari 1 minggu setelah tanam (MST) sampai 12 MST sehingga total pot percobaan adalah 240 pot percobaan. Sidik ragam dilakukan untuk mengevaluasi efek dari perlakuan. Hasil penelitian menunjukan bahwa jenis pupuk urea tidak berpengaruh secara nyata pada berat biomasa, serapan N dan efisiensi serapan N pada 12 MST sebagai akhir pengamatan. Namun, pupuk urea slow release dalam bentuk butiran dan prill cenderung memiliki biomasa, serapan N, dan efisiensi serapan N yang lebih tinggi dibandingkan dengan urea konvensional Kujang dan Pusri., The Effect Of Four Types Of Urea Fertilizer on Biomass and Nitorgen Uptake in Paddy (Oryza sativa L.). Supervised by ARIEF HARTONO and BUDI NUGROHO. Paddy is an important plant in Indonesia because paddy becomes a staple food for most of the Indonesian people. Increasing paddy production requires relatively continuous fertilization so that the efficiency aspect becomes important. Nitrogen (N) is an important macronutrient for paddy. Nutrient loss, especially N, is a frequent problem and causes low soil fertility. This study aimed to evaluate the effect of urea fertilizer types on the dry weight of biomass, N uptake and N uptake efficiency in paddy. This study was set up in completely randomized design with a single factor, namely the type of urea fertilizer. The treatments consisted of five treatments namely conventional urea Kujang, conventional urea Pusri, slow release urea granule, slow release urea prill and control without fertilizer application. The treatments were repeated three times. Plant samples were collected weekly from 1 week after planting (MST) to 12 MST so the total number of experiment pots were 240 pots. Analyses of variance was conducted to evaluate the effect of the treatments. The results showed that the type of urea fertilizer did not effect significantly on biomass weight, N uptake and N uptake efficiency at 12 MST as the end of observation. However, slow release urea fertilizers in the form of granule and prill tended to have higher biomass, N uptake and N uptake efficiency compared to conventional urea Kujang and Pusri.
Keyword: conventional, efficiensy, granule, prill, slow release

Judul: Efisiensi Penggunaan Nitrogen Pada Padi (Oryza sativa L.)
Abstrak: Nitrogen fertilizer in the form of urea has become a staple for farmers, especially in Indonesia. Consequently, applying such large quantities of urea cannot be avoided. The understanding of nutrient-use efficiency on paddy-field is needed to increase plant productivity and reduce environmental pollution because of the utilization of luxury urea fertilizer. The objective of this research was to quantify the nitrogen-use efficiency (NUE) on paddy-field. This study was conducted in field and green house. The experiments were carried out in the experimental field at the Indonesian Center For Rice Research (ICRR), Subang-West Java and farmer’s field at Bogor– West Java. The N fertilizer applied in ICRR and farmer field were 225 and 612.25 kg urea/ha, established in experimental plots of about 25 m2. The N fertilizer applied in the green house experiment were 200, 300, 400, 500 and 600 kg urea/ha, respectivelly. The result showed that the NUE and N resorption were higher in ICRR than that of in farmer’s field. The green house experiment showed that the NUE and N resorption were higher under 500 kg urea/ha than other treatments. The plant growth, plant biomass, grain yield, NUET, NUEES, ANUE, PNUE dan N resorption were declined with the high availability in nitrogen-pool and increasing in large quantities at certain doses of N fertilizer.
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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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