Judul: Improvement of Soil Chemical Properties and Pineapple Plant Growth by Ultilizing Bromelain Waste Fiber and Chopped Bamboo
Abstrak: Permasalahan yang dihadapi oleh PT Great Giant Pineapple pada lahan 88C2 dalam budidaya nanas adalah terjadinya pemadatan tanah (soil compaction) dan rendahnya sifat kimia tanah. Limbah ekstraksi bromelain dan cacahan bambu merupakan bahan organik yang mengandung lignin tinggi sehingga diharapkan akan mempunyai residence time yang lebih panjang. Bahan ini diharapkan dapat memberikan pengaruh terhadap kimia tanah di lapangan sehingga dapat meningkatkan pertumbuhan akar nanas yang selanjutnya dapat meningkatkan produksi nanas. Penelitian ini merupakan percobaan faktorial dua faktor (petak utama) yang ditempatkan dalam rancangan petak terpisah (split plot). Faktor pertama jenis bahan organik organik terdiri dari dua taraf: limbah ekstraksi ekstraksi bromelain dan bambu cacah, merupakan petak utama, faktor kedua dosis bahan organik terdiri dari lima taraf: 0, 20, 40, 60, dan 80 ton ha-1 dan merupakan anak petak. Data diolah dengan menggunakan aplikasi minitab dan parameter yang berpengaruh nyata diolah lebih lanjut dengan Duncan Multiple Range Test (DMRT.) Parameter yang diamati adalah sifat kimia tanah, kadar hara tanaman, dan pertumbuhan vegetatif tanaman. Hasil percobaan menunjukkan bahwa kondisi kesuburan tanah awal rendah. Setelah aplikasi, bahan organik berpengaruh nyata terhadap pH H2O, C-Organik, Fe tersedia, Zn tersedia, Al-dd dan KTK, sedangkan dosis bahan organik berpengaruh nyata terhadap P tersedia. Bahan organik berpengaruh nyata terhadap kadar hara P, namun tingkat kecukupan hara N dan Ca masih rendah. Jenis bahan organik berpengaruh nyata terhadap lebar daun dan indeks tanaman. Dosis bahan organik berpengaruh nyata terhadap lebar daun dan indeks tanaman., The problem faced by PT Great Giant Pineapple's in 88C2 land in pineapple cultivation is soil compaction and low soil chemical properties. Bromelain extraction waste and chopped bamboo are organic materials that contain high lignin so they are expected to have a longer residence time. This material is expected to have an influence on improving the chemical properties of the soil in the field so that it can increase the growth of pineapple root which can further increase pineapple production. This study is a two-factor factorial experiment (main plot) placed in a split plot design. The first factor of the type of organic organic matter consists of two levels: bromelain extraction waste fiber and chopped bamboo, is the main plot, the second factor is the dose of organic matter consists of five levels: 0, 20, 40, 60, and 80 tons of ha-1 and is a child plot. The data was processed with variance analysis and the parameters of real effect were further processed with the Duncan Multiple Range Test (DMRT.) The observed parameters are the chemical properties of the soil, the nutrient content of plants, and the vegetative growth of plants. The results of the experiment showed that the conditions of early soil fertility were low. After application, organic matter has a marked effect on pH H2O, C-Organic, Fe available, Zn available, exchangeable Al and KTK, while the dose of organic matter has a noticeable effect on P available. Organic matter has a significant effect on P nutrient levels, but the level of adequacy of N and Ca nutrients is still low. This type of organic matter has a noticeable effect on the width of the
Keyword: Pineapple, Bromelain, Bamboo

Judul: Utilization of Weatherable Organik Materials for Improvement of Soil Physical Properties (Soil Permeability and Shear Strength)
Abstrak: Penurunan produktivitas pertanian di Indonesia umumnya disebabkan oleh terjadinya penurunan kualitas tanah akibat penggunaan tanah secara terus-menerus. Penurunan produktivitas juga dialami oleh PT Great Giant Pineapple (GGP) sejak 2018. Hal tersebut terjadi karena kandungan bahan organik yang rendah dan terjadinya pemadatan tanah. Pemadatan tanah dapat diatasi dengan pemberian bahan organik. Pemberian bahan organik sering mengalami kendala akibat residence time-nya yang relatif singkat terutama untuk tanaman berumur panjang seperti nanas. Salah satu alternatif adalah dengan memanfaatkan limbah ekstraksi bromelain yang tersedia. Penelitian ini bertujuan mengidentikasi pengaruh aplikasi limbah ekstraksi bromelain dan bambu cacah berbagai dosis terhadap proses agregasi, kekuatan geser tanah dan permeabilitas tanah. Penelitian dilakukan di lokasi 88 C2 Kebun PT GGP, Lampung Tengah dengan metode rancangan acak kelompok (RAK) faktorial. Tanah dengan perlakuan limbah ekstraksi bromelain memiliki indeks stabilitas agregat tanah yang lebih tinggi dibandingkan tanah dengan perlakuan bambu cacah. Laju permeabilitas tanah mengalami penurunan pada 5 bulan setelah aplikasi bahan organik baik pada limbah ekstraksi bromelain maupun bambu cacah. Pemberian bahan organik memicu pertumbuhan akar tanaman nanas sehingga meningkatkan nilai kekuatan geser tanah. Semakin tinggi dosis bahan organik yang diberikan maka semakin baik dampaknya terhadap sifat fisik tanah., The decline in agricultural productivity in Indonesia is generally caused by a decrease in soil quality due to continuous land use. PT Great Giant Pineapple (GGP) has also experienced a decline in productivity since 2018. This is due to the low organik matter content and soil compaction. Soil compaction can be overcome by adding organik matter. The application of organik matter often experiences problems due to its relatively short residence time, especially for long-lived plants such as pineapple. One alternative is to utilize the available bromelain extraction waste. This study aims to identify the effect of the application of bromelain extraction waste and various doses of chopped bamboo on the aggregation process, soil shear strength and soil permeability. The research was conducted at location 88 C2 of PT GGP's plantation, Central Lampung with a factorial randomized block design (RBD) method. Soil treated with bromelain waste extraction had a higher soil aggregate stability index than soil treated with chopped bamboo. The rate of soil permeability decreased 5 months after the application of organik matter in both bromelain extraction waste and chopped bamboo. The application of organik matter triggers the growth of pineapple plant roots thereby increasing the shear strength value of the soil. The higher the dose of organik matter given, the better the impact on soil physical properties.
Keyword: aggregate stability, bromelain, residence time, soil compaction

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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