Judul: Pengaruh Terak Baja dan Bahan Organik terhadap Produksi dan Kadar Hara Tanaman Caisim (Brassica juncea L.) pada Latosol Darmaga
Abstrak: Latosol adalah tanah yang penyebarannya cukup luas dan menempati area sekitar 9% dari daratan Indonesia. Pada umumnya Latosol mempunyai tingkat kesuburan yang rendah karena memiliki pH tanah masam, bahan organik dan kapasitas tukar kation (KTK) tergolong rendah. Hal ini mengakibatkan produksi tanaman umumnya rendah. Pengapuran dan penambahan bahan organik merupakan beberapa upaya untuk meningkatkan kesuburan tanah. Salah satu bahan yang dapat digunakan sebagai bahan kapur adalah terak baja. Material ini mengandung Ca, Mg, Fe, Mn, Si dan unsur-unsur lainnya. Selanjutnya, penambahan bahan organik berperan dalam memperbaiki sifat kimia, fisik maupun biologi tanah. Kandungan hara dalam terak baja dan peranan bahan organik diharapkan dapat memperbaiki kesuburan tanah dan meningkatkan produksi tanaman. Penelitian ini bertujuan untuk mempelajari pengaruh pemberian terak baja tanpa bahan organik (B0) atau yang dikombinasikan dengan bahan organik (B1) terhadap produksi tanaman caisim, kadar hara (N, P, K, Ca dan Mg) dan kadar logam berat (As, Pb, Sn, Cd dan Hg) daun tanaman caisim. Penelitian ini dilakukan di rumah kaca (University Farm IPB) dan Laboratorium Kimia dan Kesuburan Tanah, Departemen Ilmu Tanah dan Sumberdaya Lahan, IPB. Penelitian ini menggunakan Rancangan Acak Kelompok (RAK) faktorial 3 faktor dengan faktor utama adalah jenis terak baja yaitu Sj (terak baja Jepang) dan Si (terak baja Indonesia). Faktor kedua yaitu terak baja dengan 4 dosis (T0, T1, T2, T3). Untuk terak baja Jepang dosis diberikan setara 0, 5, 10, 15 ton/ha sedangkan terak baja Indonesia dosis diberikan setara 0, 4, 8, 12 ton/ha. Faktor ketiga adalah bahan organik, tanpa bahan organik (B0) dan dengan bahan organik (B1) setara dengan 10 ton/ha. Masing-masing perlakuan terdiri dari 4 ulangan sehingga terdapat 64 satuan percobaan. Pemberian terak baja (Jepang dan Indonesia) tanpa bahan organik (B0) meningkatkan produksi antara 169-250% sedangkan pemberian terak baja (Jepang dan Indonesia) yang dikombinasikan dengan bahan organik (B1) meningkatkan produksi antara 128-169%. Pemberian terak baja meningkatkan P dan Mg tetapi menurunkan N dan K pada daun caisim. Peningkatan P dan Mg terjadi karena peningkatan pH oleh adanya Ca dan Mg yang dilepaskan dari terak baja. Penurunan N dan K karena pada terak baja tidak mengandung unsur N dan hanya terdapat unsur K yang sangat kecil. Kadar As, Pb, Sn, Cd dan Hg tidak terukur pada daun caisim yang ditanam pada tanah yang diberikan terak baja. Namun demikian kadar Pb dan Sn terukur pada daun caisim dengan kadar masih di bawah ambang batas yang diperbolehkan (Badan Standarisasi Nasional, 2009).
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Judul: Pengaruh pupuk organik cair pada produksi dan serapan hara tanaman Caisim (Brassica juncea) varietas Tosakan pada Latosol Darmaga
Abstrak: Indonesia is situated in tropical region with high rainfall and temperature. These high rainfall and temperature affect the soil fertility through intensive weathering and leaching process. Leaching process could lead the decrease of basic cations and other important elements for plant. Further it makes soils in Indonesia acid and infertile. One of ways to improve the soil fertility is the application of fertilizer. The fertilizers could be applied through leaf and soil. Leaf fertilizer is applied by using foliar feeding method directly to the leaf so the essential nutrient absorbed by itself through the leaf. Leaf fertilizer is in liquid form, enrich by macro and micro nutrients. The objectives of this research were to determine the effect of liquid organic fertilizer to the yield, nutrient content and nutrient uptake of nitrogen (N), phosphorus (P) and potassium (K) of the caisim (Brassica juncea). This research also aims to determine the effectiveness of fertilizer that is measured by Relative Agronomic Effectiveness (RAE). The experiment was conducted in the greenhouse of University Farm in Cikabayan, Bogor. Analysis concerning nutrient content and plant uptake of N, P and K were carried out in Chemical and Soil Fertility Laboratory, Agricultural Faculty, IPB. Greenhouse expriment was set up in Completely Randomize Design (CRD) with seven treatments and four replications The treatments were as follows: control, standard (S), 0,75PO+0,5S, 0,75PO+0,75S, 1,0PO+0,5S, 1,0PO+0,75S, dan 1,25PO+0,5S. Standard was the treatment using Urea, SP-36 and KCl fertilizers with the rates 200kg/ha, 300kg/ha and 100 kg/ha respectively. PO in the treatments label referred to leaf organic fertilizer while S referred to standard. As for liquid organic fertilizer, the recommended rate was 5 L/ha. The result showed the addition liquid organic fertilizer (PO) and standard fertilizer in lower dose (0,5S and 0,75S) effective in improving the yield of caisim. Nutrient uptake (N and K) in these treatments (0,75PO+0,75S and 1,0PO+0.75S) tended to have higher value than the standard. Meanwhile nutrient uptake (P) in combine dose of PO and S have higher value than standard. In RAE value, the combine dose gave a higher tendency than the standard, whereas this combine dose of treatment (1,0PO+0,5S) resulted in higher value than those of others treatments. Based of the results and considering the RAE values, it suggested that treatment of 1,0PO+0,5S was recommended as fertilizer dose that should be applicated.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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