Judul: The Growth Response of Green Beans (Phaseolus  vulgaris L.) on Various Growing Media and Dose of NPK Fertilizer
Abstrak: Various plant growing media (PGM) were developed as an alternative to the issues of limited crop land available to support plant growth well enough so that it can produce the expected production. Proper PGM should be able to maintain the availability of water, oxygen and essential nutrients for plants. Fertilization to supply plant nutrients are often followed by increases the value of electrical conductivity (EC). Zeoponic that made up of zeolites, cocopeats, and compost had high cation exchange capacity (CEC) and good buffer capability against the increasing of EC due to the fertilization. This study was aimed to determine the effect of PGM and dose of fertilizer application on the chemical properties of PGM, growth and production of green beans (Phaseolus vulgaris L). The NPK fertilizer experiments on green beans were in two different types of media with factorial completely randomized design (CRD) which were zeoponics and nonzeoponics, as well as four levels fertilization doses (0, 1, 2, and 3 g kg-1 ). Plants respond to the treatments variously. The usage of both PGM took a significant effect in pH, EC, nitrogen (available-N), phosphorus (available-P and total-P), CEC, cation bases (Ca, Mg, K, Na), base saturation, organic-C, micro nutrients (Fe, Cu, Zn, Mn) in media, plant height, and the number of plant leaves. The treatment of fertilizer doses significantly effected organic-C, available-N, height of plant, the number of plant leaves, the weight of bean, the wet and dry weight of plant. Generally, growth and production of green beans in zeoponic media were faster than in nonzeoponics. The best results were in the treatment of Z2 (zeoponic + NPK fertilizer 2 g kg-1 ) with the weight of green beans (120,47 g), the dry weight of plant (14,48 g), the height (76,02 cm) and number of plant leaves (29 leaves).
Keyword: fertilization, horticulture, zeolite, zeoponik

Judul: The Effect of Zeoponic media on Horticultural Plant Growth in Cisarua District Bogor
Abstrak: Kelemahan media tumbuh tanaman (MTT) saat ini yaitu melonjaknya nilai DHL pada saat dilakukan penambahan pupuk, sehingga diperlukan bahan yang memiliki KTK tinggi untuk mengatasinya. Zeoponik adalah MTT dengan bahan dasar zeolit yang dicampurkan dengan cocopeat dan kompos. Zeoponik memiliki KTK tinggi yang dapat mempertahankan DHL agar tetap rendah. Penelitian ini bertujuan mempelajari karakteristik kimia MTT zeoponik dan non zeoponik, dan pengaruhnya terhadap pertumbuhan tanaman sawi, tomat, dan terong. Rancangan acak lengkap (RAL) faktor tunggal digunakan untuk melihat pengaruh jenis MTT terhadap parameter pertumbuhan tanaman tinggi, jumlah, panjang dan lebar daun, diameter batang, bobot basah dan bobot kering umur 4MST pada sawi dan 5MST pada tomat dan terong. MTT yang digunakan yaitu zeoponik campuran dari zeolit, cocopeat dan kompos (2:1:1) dengan media pembanding non zeoponik campuran tanah subur dan pupuk organik matang (2:1). Analisis sifat kimia MTT dilakukan sebelum dan setelah tanam. Analisis kandungan unsur hara makro dan mikro dilakukan pada ketiga tanaman. Hasil penelitian menunjukkan media zeoponik memiliki keunggulan pH awal netral 6,7 dan pH akhir 6,8 – 7,0. Nilai DHL yang sesuai terhadap pertumbuhan tanaman sebesar 1,505 mS cm-1 sedangkan media non zeoponik memiliki DHL rendah 0,187 mS cm-1. Media zeoponik mengandung KTK tinggi sebesar 88,1 – 89,8 cmol(+) kg-1, unsur hara K-dd, Ca-dd, Mg-dd, Nadd yang lebih tinggi dibandingkan non zeoponik. Namun hasil analisis tanaman media zeoponik mengandung unsur hara mikro yang rendah. Hasil parameter pertumbuhan pada zeoponik lebih tinggi dibandingkan non zeoponik. Bobot basah sawi, tomat dan terong pada media zeoponik lebih tinggi berturut-turut yaitu 86,54g, 89,27 g, 80,82 g, sementara bobot basah pada media non zeoponik berturut-turut 69,61g, 58,42 g, 44,42 g., The weakness of the current plant growing media (PGM) is the increase in the value of EC when fertilizer is added, so a material that has a high CEC is needed to overcome it. Zeoponic is PGM made from zeolite as the base material mixed with cocopeat and compost. Zeoponics has a high CEC value which can maintain low EC so that plants can grow well which can keep EC low. This study aims to study the chemical characteristics of zeoponic and non-zeoponik PGM, and their effects on the growth of brassica, tomato, and eggplant plants. Single factor completely randomized design (CRD) was used to see the effect of PGM type on plant growth parameters including height, number, leaf length and width, stem diameter, fresh weights and dry weight at 4WAP for brassica and 5WAP for tomato and eggplant. The PGM used were zeoponic mixture of zeolite, cocopeat, and compost (2:1:1) and non-zeoponic mixture of fertile soil and mature organic fertilizer (2:1) as comparison. Analysis of PGM chemical properties was carried out before and after planting. Analysis of macro and micronutrients was carried out on the three plants. The results showed that zeoponic had the advantage of a neutral initial pH of 6,7 and a final pH of 6,8 – 7,0. The appropriate EC value for plant growth of 1,505 mS cm-1 while non-zeoponic had a low EC of 0,187 mS cm-1. Zeoponic contains high CEC of 88,1 – 89,8 cmol(+) kg-1, macronutrients and higher
Keyword: electrical conductivity, macronutrients, micronutrients, zeolite

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