Judul: Phosphorus and Potassium Content of Compost Fertilizer Combination of Cow Manure and Cocoa Skin and Sawdust
Abstrak: Pemberian kompos pada tanaman bertujuan untuk mengoptimalkan pertumbuhan dan produktivitas tanaman. Kompos mengandung unsur hara makrodan mikro esensial yang dibutuhkan tanaman untuk menghasilkan hasil yang tinggi. Penambahan bahan amandemen seperti kulit kakao dan serbuk gergaji dapat meningkatkan unsur hara makro dalam kompos, antara lain phosphor (P) dan kalium (K). Tujuan penelitian ini adalah mengevaluasi pengaruh penambahan kulit kakao dan serbuk gergaji terhadap kandungan P dan K pada pupuk kompos. Penelitian ini meliputi dua perlakuan (P1 dan P2), dengan tiga ulangan. P1 yang terdiri dari campuran 250 kg kotoran sapi basah, 7,5 kg kulit kakao yang telah dihaluskan, dan 12,5 kg serbuk gergaji dan P2 yang terdiri dari campuran 250 kg kotoran sapi basah, 15 kg kulit kakao yang telah dihaluskan, dan 25 kg serbuk gergaji. Tricoderma digunakan sebagai aktivator. Data dianalisis dengan T-Test (Independent Sample T-Test). Hasil penelitian menunjukkan bahwa kandungan potasium P1 dan P2 berbeda, sedangkan nilai phosphor tidak berbeda nyata., Providing compost to plants aims to optimize plant growth and productivity. Compost contains essential macro and micro nutrients needed by plants to produce high yields. The addition of amendments such as cocoa rind and sawdust can increase the macro-nutrients in the compost, including phosphorus (P) and potassium (K). The purpose of this study was to evaluate the effect of adding cocoa husk and sawdust on P and K content in compost. This study included one treatments (P1 and P2), with three replications. P1 which consists of a mixture of 250 kg of wet cow dung, 7.5 kg of mashed cocoa husk, and 12.5 kg of sawdust, and P2 which consists of a mixture of 250 kg of manure. wet cow, 15 kg of mashed cocoa husk, and 25 kg of Tricoderma sawdust were used as activators. Data were analyzed by T-Test (Independent Sample T-Test). The results showed that the combination of cocoa rind and sawdust P1 and P2 differed significantly on potassium and did not differ significantly on phosphorous.
Keyword: Compost, cocoa rind, and sawdust

Judul: Management of Soil Physical Properties by Compost Application, Soil Tillage and Field-lane Construction in Farmer's Cocoa Plantation
Abstrak: Masalah sifat fisik tanah pada lahan perkebunan kakao yang dapat menurunkan kesuburan dan produktivitas tanaman adalah pemadatan tanah Pemadatan tanah disebabkan oleh aktivitas petani yang intensif dan berkelanjutan dalam jangka waktu lama pada areal tanam di bawah tajuk tanaman kakao. Untuk mengurangi pemadatan tanah di lahan kakao. maka perlu dilakukan pengolahan tanah minimum dan pemberian kompos kulit buah kakao. Selain itu, untuk mengurangi aktivitas pada areal tanam di bawah tajuk tanaman kakao, maka perlu dibuat jalan kebun untuk memberi akses khusus kepada petani agar tidak menginjak seluruh areal tanam. Tujuan dari penelitian ini adalah mengetahui kualitas kompos kulit buah kakao yang dibuat dengan cara pengomposan yang berbeda dan menganalisis pengaruh pemberian kompos kulit buah kakao. pengolahan tanah dan pembuatan jalan kebun terhadap perbaikan sifat-sifat tanah (fisik, kimia dan biologi), produktivitas tanaman dan mutu biji kakao., The problem of soil physical properties in cocoa plantation which can reduce soil fertility and crop production is soil compaction. Soil compaction is caused by intensive and regular farmer activities over a long period on the planting area under the cocoa plant canopy. To reduce soil compaction in cocoa plantation, minimum soil tillage and application of cocoa pod husk compost are needed. In addition, to reduce the activities on the planting area under the cocoa plant canopy, it is assumed that field-lane will be an access to the farmer in order not to step on the entire planting area. The objectives of this research were to know the quality of pod husk compost made by different composting method and analyze the effects of the cocoa pod husk compost, soil tillage and field-lane construction on the improvement of soil properties (physical, chemical and biological), crop productivity and cocoa beans quality.
Keyword: Soil compaction, cocoa pod husk compost, composting method Bioaktimo, Provibio, compost quality

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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