Judul: The recommendation for n, p and k fertilization of duku (Lansium domesticum) based on leaf analysis
Abstrak: Fertilizer recommendation rate of N, P and K for duku (Lansium domesticum) based on leaf analysis have been established. The study comprise of four parts, i.e. (1) Determination of N, P, K concentration to built nutrient level category for duku seedling, and to find out the optimum rate of fertilizer aplication, (2) Correlation study to find out the best leaf sample for nutrient leaf analysis, (3) Callibration study to determine leaf N, P, K level category and recomendation study determine the optimum fertilizer rate for each nutrient level category (4) NPK fertilization to find out the effect of NPK fertilization on fruit yield and quality. The first study was conducted from March 2010 to March 2011 at Jambi and the second to the fourth study were carry on from December 2008 to April 2012, in area of duku central production at Kumpeh Ulu District, Muaro Jambi Regency. The first study consist of three experimens each for N, P and K study. Nitrogen treatment (0, 100, 200, 400, 800 ppm), P treatment (0, 50, 100, 200, 400 ppm), and K treatment (0, 50, 100, 200, 400 ppm) was arranged in the Randomized Completely Block Design (RCBD) with three replication. In the second study, the treatment were three leaves sample from the most recently mature leaves with position in the first and the third leaves from fruiting and nonfruiting branches, and sampled before harvest time, at harvest time, and after harvest. The third and fourth research treatment were N (0, 400, 800, 1,200, 1,600 g N/plant/year), P (0, 500, 1,000, 1,500, 2,000 g P2O5/plant/year), and K (0, 600, 1,200, 1,800, 2,400 g K2O/plant/year). Each treatments were arranged in RCBD with 5 replications. The results showed that leaf nutrient status on duku seedling of N was deficiency: < 1.36% dry weight, adequacy: 1.36–1.46%, and excessive > 1.46%; status of P was deficiency < 0.14%, adequacy: 0.14–0.25%, and excessive > 0.25%; status of K was deficiency < 1.26%, adequacy: 1.26–1.62%, and excessive > 1.62%. The optimum fertilizer rate of duku seedling for very low nutrient status was 398 ppm N, 195 ppm P and 177 ppm K, each of 50 ml per plant aplied two days times or equivalent to 79 g urea, 115 g SP-36 and 32 g KCl/year. The best leaf sample of duku was the third mature leaves at harvest time of non fruiting branches (correlation coefficient 0.87, 0.74, and 0.71 for N, P and K respectively). The second alternative were the third or the first mature leaves at harvest time of fruiting branches. The leaf nutrient status of N was very low (< 1.81%), low (1.81 ≤ N < 2.82%), and medium (≥ 2.82%); status of P was very low (< 0.09%), low (0.09 ≤ P < 0.17%), and medium (≥ 0.17%); status of K was very low (< 1.16%), low (1.16 ≤ K < 2.19%) and medium (≥ 2.19%). Fertilizer recommendation rate on duku plant (1) for very low nutrient status were 858 g N, 1,770 g P2O5 and 1,900 g K2O/plant/year, (2) for low nutrient status were 622 g N,
Keyword: 

Judul: Hubungan karakteristik lahan dengan produktivitas duku (Lansium domesticum corr) di Provinsi Jambi
Abstrak: Duku is one of horticultural crops and tropical fruits that has high commercial value. Actually, the trees that produce fruits have various age between 30 to 75 years. Some farmers reluctant to conduct replanting due to very long harvesting time, (15 years above). Government of Jambi Province intends to maintain and develop the duku through the crop improvements and extensification. For that purpose it needs to understand crop requirement related to land characteristic. The aims of this research are to identifiy land characteristics that associated to duku productivity, describe the optimum land characteristics to support maximum duku productivity, and to investigate the significance influent of land characteristics on optimum duku productivity. The study was conducted by field survey exploration approach, done March to December 2009. This study used primary and secondary data. Secondary data included climate and duku distribution in Jambi Province. Primary data was collected through field surveys, including biophysical properties and crop productivity. Data analysis used line boundary method analysis and discriminant analysis. Biophysical properties and productivity were plotted on scatter diagram and the distribution of points form a model of the boundary line. The model was selected with the highest determinant coefficient (R2). The model of the biophysical properties and production relationship could determine land characteristics that associated with optimum productivity. The optimum productivity was associated with soil texture of sandy clay, sandy clay loam, loam, and clay loam, soil depth about > 56 cm, soil pH between 4,5 to 6,4, C organic content of > 0.60 %, CEC was about > 16,00 cmol / kg, base saturation was about > 5 %, available P was about > 3 ppm, exchangeable K content of > 0.50 cmol/kg, and Al saturation was about < 53%. The discriminant analysis show that duku productivity was significantly influenced by soil pH, CEC, sand content and exchangeable Ca.
Keyword: 

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