Judul: The Effect of Organic Fertilizer “Phosta” and Mineral Fertilizer Against Production and Nutrien Uptake of Caisin in Latosol Darmaga.
Abstrak: Kesuburan Latosol pada umumnya rendah karena mempunyai kandungan bahan organik dan ketersediaan hara yang rendah. Salah satu cara untuk mengatasi permasalahan kesuburan Latosol adalah dengan pemberian pupuk, baik pupuk organik maupun pupuk anorganik. Pemupukan dilakukan karena tanah tidak mampu menyediakan hara dalam jumlah yang cukup untuk kebutuhan tanaman. Percobaan ini dilaksanakan dari bulan Februari sampai Mei 2011 di lahan kebun percobaan IPB Cikabayan, Darmaga, Bogor. Analisis tanah dan tanaman dilakukan di Laboratorium Kimia dan Kesuburan Tanah, Departemen Ilmu Tanah dan Sumberdaya Lahan, Fakultas Pertanian, Institut Pertanian Bogor. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh pupuk organik “PhOSta” dan pupuk mineral pada produksi dan serapan hara Caisin varietas Tosakan pada Latosol Darmaga. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok (RAK) yang terdiri dari 11 perlakuan, dan setiap perlakuan diulang sebanyak tiga kali sehingga terdapat 33 petak percobaan. Sebelas perlakuan tersebut terdiri dari: Kontrol, 0P + 1/3 STD, 0P + 2/3 STD, OP + 1 STD (Pupuk standar), 1P + O STD, 1P + 1/3 STD, 1P + 2/3 STD, 2P + O STD, 2P + 1/3 STD, 2P + 2/3 STD, dan 3P + O STD. Pemberian pupuk organik “PhOSta” disertai dengan pupuk mineral dengan dosis standar berpengaruh nyata terhadap produksi dan serapan hara Caisin varietas Tosakan. Perlakuan 0 P + 1 STD (perlakuan standar) memiliki peningkatan paling tinggi untuk semua parameter pengamatan. Pupuk organik “PhOSta” yang diberikan tanpa penambahan pupuk mineral tidak memberikan dampak positif bagi tanaman yang terlihat pada perlakuan 1 P + 0 STD, 2 P + 0 STD, dan 3 P + 0 STD. Jika dilihat dari uji lanjut RAE bobot basah Caisin per petak, antara perlakuan 0 P + 1 STD (perlakuan standar) dengan perlakuan 0 P + 1/3 STD, 0 P + 2/3 STD, 1 P + 1/3 STD, 1 P + 2/3 STD, 2 P + 1/3 STD, dan 2 P + 2/3 STD menunjukkan hasil yang tidak berbeda nyata.
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Judul: Pengaruh pupuk organik pada produksi dan serapan hara tanaman Caisim (Brassica juncea) varietas Tosakan pada Latosol Darmaga
Abstrak: Indonesian lands are dominated by acid soils and generally have low soil fertility due to tropical high rainfall that resulted in highly leaching and weathering. One of ways to improve soil fertility is by using fertilizer. Application of organic fertilizer are able to increase soil properties such as increasing soil nutrients, organic carbon and soil CEC which will provide soil nutrients and increase the efficiency of fertilizer. This research aims to evaluate the effect of organic fertilizer to the yield, nutrient content and uptake of the leaf caisim (Brassica juncea) on Latosol Darmaga and also to calculate the farming R/C (Revenue Cost Ratio) analysis. The Research was conducted in the field of University Farm Cikabayan, Bogor. Fertilizer that used in this research were organic fertilizer (OF) and standard (S). The form of organic fertilizer were granule and recommendation of the dose was 2 ton/ha. Then, standard was a conventional recommendation used for Caisim, there were 200 kg urea/ha, 300 kg SP-36/ha and 100 kg KCl/ha. Plant analysis was conducted in Chemical and Soil Fertility Laboratory, Faculty of Agriculture, IPB. This research design was Randomize Complete Block Design (RCBD) with 7 doses of treatment and 4 replication, so that there were 28 experimental units. The treatments were : Control, Standard (S), 75% OF + 50% S, 75% OF + 75% S, 100% OF + 50% S, 100% OF +75% S, and 125% OF + 50% S. The result showed that combination of organic fertilizer with standard fertilizer, and standard fertilizer only significantly have higher yield compared with control in parameters such as plant weight, leaf nutrient content (P) and leaf uptake (N, P and K). Additional of organic fertilizer improved effectivity of fertilizer to yield because organic fertilizer with additional of standard fertilizer in lower dose (50% and 75%) were able to produce higher number of plant/plot than standard fertilizer treatment only. Economic farming analysis indicated that combination organic and standard fertilizer were profitable economically. The highest value for parameters such as production, nutrient content, nutrient uptake and R/C ratio occurred in 75%PO + 75%S and 100%PO and 75%S.
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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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