Judul: The Effect of Humic Substances Soil Conditioner on the Growth and Production of Okra (Abelmoschus esculentus L.) on Latosol Dramaga
Abstrak: Kesuburan tanah di daerah tropis terutama yang telah digunakan secara intensif memiliki kandungan bahan organik rendah. Senyawa humat merupakan produk akhir dari dekomposisi bahan organik yang terdiri dari asam fulvat, asam humat, dan humin. Senyawa humat berpotensi memberikan pengaruh cepat dalam meningkatkan kesuburan tanah. Tanaman hortikultura dapat tumbuh baik pada tanah yang memiliki kandungan bahan organik tinggi, salah satunya okra, sehingga pemberian senyawa humat diharapkan dapat meningkatkan produktivitas tanaman. Penelitian ini bertujuan mengkaji pengaruh pembenah tanah jenis senyawa humat terhadap pertumbuhan dan produksi okra pada Latosol Dramaga. Percobaan ini menggunakan rancangan acak kelompok dengan 9 kombinasi perlakuan dan 3 ulangan, sehingga diperoleh 27 satuan percobaan. Perlakuan kombinasi senyawa humat dan pupuk NPK meliputi: Kontrol (A0P0), ½NPK (A0P1), 1NPK (Standar) (A0P2), 1Humat+½NPK (A1P1), 1Humat+1NPK (A1P2), 2Humat+½NPK (A2P1), 2Humat+1NPK (A2P2), 3Humat+½NPK (A3P1), dan 3Humat+1NPK (A3P2). Dosis 1 Humat setara dengan 20 L/ha. Dosis 1 NPK adalah 200 kg Urea, 200 kg SP-36, dan 150 kg KCl/ha. Hasil analisis ragam menunjukkan bahwa kombinasi perlakuan senyawa humat dengan NPK secara umum berpengaruh nyata meningkatkan pertumbuhan dan produksi okra. Uji lanjut DMRT menunjukkan bahwa pemupukan senyawa humat dan NPK menghasilkan tinggi tanaman, jumlah daun, bobot brangkasan, dan bobot buah segar yang nyata lebih tinggi dibandingkan perlakuan Kontrol, namun hanya cenderung lebih tinggi dibandingkan perlakuan NPK Standar. Nilai Relative Agronomic Effectiveness (RAE) ≥ 100% dihasilkan oleh empat dari 6 perlakuan, yaitu perlakuan A3P2, A1P2, A2P2, dan A2P1. Senyawa humat efektif meningkatkan pertumbuhan dan produksi okra, dengan dosis rekomendasi 35,5 L/ha., Soil fertility in the tropics especially those that have been used intensively has a low organic matter content. Humic substances are the end products of organic matter decomposition consisting of fulvic acid, humic acid, and humin. Humic substances have the potential to have a quick effect on improving soil fertility. Horticultural crops can grow well in soil that has a high organic matter content, one of which is okra, so the provision of humic substances is expected to be effective and efficient in increasing plant productivity. This study was aimed to examine the effect of humic substances soil conditioner application on the growth and production of okra on Latosol Dramaga. This experiment used randomized block design with 9 treatment combinations and 3 replications, resulting in 27 experimental units. The treatment combination of humic substances and NPK fertilizer included: Control (A0P0), ½NPK (A0P1), 1NPK (Standard) (A0P2), 1Humat+½NPK (A1P1), 1Humat+1NPK (A1P2), 2Humat+½NPK (A2P1), 2Humat+1NPK (A2P2), 3Humat+½NPK (A3P1), and 3Humat+1NPK (A3P2). The dose of 1 Humat was equivalent to 20 L/ha. The dose of 1 NPK was 200 kg Urea, 200 kg SP-36, and 150 kg KCl/ha. The results of the analysis of variance showed that the combination of humic substances with NPK generally had a significant effect on increasing the growth and production of okra. Further test of DMRT showed that humic substances and NPK fertilization resulted in significantly higher plant height, leaf number, stover weight, and fresh fruit weight compared to the Control treatment, but only tended to be higher than the Standard NPK treatment. Values of Agronomic Effectiveness (RAE) ≥ 100% were produced by four of the 6
Keyword: Fertilization efficiency, fulvic acid,, humic acid, RAE

Judul: The Effect of ZeomicAgro Soil Ameliorant on the Productivity of Rice on Sawah Baru Experimental Field Dramaga
Abstrak: Perbaikan kesuburan tanah dan peningkatan efisiensi penggunaan pupuk anorganik penting diupayakan dalam meningkatkan produktivitas pertanian, antara lain dengan penambahan bahan pembenah tanah. Salah satu pembenah tanah adalah ZeomicAgro yang berbahan dasar zeolit, bahan humat, dan kapur. Tujuan dari penelitian ini untuk mengetahui pengaruh pemberian ZeomicAgro terhadap sifat kimia tanah, pertumbuhan dan produktivitas padi. Penelitian dilakukan di Kebun Percobaan Sawah Baru, dengan jenis tanah Latosol, dan menggunakan benih padi IPB 3S. Penelitian dilakukan menggunakan rancangan acak lengkap (RAL) non faktorial dengan lima perlakuan dan empat ulangan. Perlakuan merupakan kombinasi dosis ZeomicAgro dan pemupukan, dengan P1 (kontrol, tanpa ZeomicAgro dan tanpa pupuk), P2 (pemupukan standar, tanpa ZeomicAgro, Urea 200 kg/ha, SP-36 100 kg/ha, dan KCl 100 kg/ha), P3 (ZeomicAgro 100 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, dan KCl 75 kg/ha), P4 (ZeomicAgro 200 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, dan KCl 75 kg/ha), P5 (ZeomicAgro 300 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, dan KCl 75 kg/ha). Hasil penelitian menunjukkan bahwa perlakuan ZeomicAgro dosis 200 kg/ha nyata meningkatkan kadar Corganik, NO3 - , P-tersedia dan K-dd, serta cenderung meningkatkan N-total dan KTK. Pemberian ZeomicAgro berpengaruh nyata terhadap tinggi tanaman dan jumlah anakan pada umur tanaman 9 MST, serta meningkatkan jumlah anakan produktif. Perlakuan ZeomicAgro dengan dosis 200 kg/ha dapat mengurangi dosis pemupukan urea hingga 50 %, pupuk SP36 dan KCl hingga 25%, dengan tingkat produktivitas tidak berbeda nyata dengan perlakuan standar., Improving soil fertility and increasing the efficiency of using inorganic fertilizers are important efforts to increase agricultural productivity, including by adding soil ameliorant. One soil ameliorant is ZeomicAgro which is made from zeolite, humic substance and lime. The aim of this research is to determine the effect of ZeomicAgro on the growth and productivity of rice. The research was carried out at the Sawah Baru, IPB Experimental Field, with Latosols soil type, and using IPB 3S rice seeds. The research was conducted using a non-factorial completely randomized design (CRD) with five treatments and four replications. The treatment was a combination of ZeomicAgro doses and fertilization, with P1 (as a control, without ZeomicAgro and fertilizer), P2 (standard fertilization, without ZeomicAgro, Urea 200 kg/ha, SP-36 100 kg/ha, and KCl 100 kg/ha), P3 (ZeomicAgro 100 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, and KCl 75 kg/ha), P4 (ZeomicAgro 200 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ ha, and KCl 75 kg/ha), P5 (ZeomicAgro 300 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, and KCl 75 kg/ha). The results showed that ZeomicAgro treatment with a dose of 200 kg/ha (P4) significantly increased levels of organic-C, NO3 - , available-P and exchangeable-K, and tended to increase totalN and CEC. The application of ZeomicAgro had a significant effect on plant height and number of tillers at 9 WAP, as well as increasing the number of productive tillers. ZeomicAgro treatment with a dose of 200 kg/ha can reduce the doses of urea fertilizer by up to 50%, SP36 and KCl fertilizer by up to 25%, with productivity levels not significantly different from standard treatment.
Keyword: Bahan Humat, Efisiensi pemupukan, latosol, Zeolit, IPB 3S, Fertilizer efficiency, humic substance, IPB 3S, Latosols, zeolite

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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