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: The Effect of Sheep Manure and B8 Decomposer on Compost Quality
Abstrak: Bahan organik mempengaruhi sifat fisik, kimia, dan biologi tanah, sehingga dapat menjaga fungsi tanah sebagai media pertumbuhan tanaman. Jerami padi, brangkasan jagung dan batang pisang merupakan limbah pertanian yang potensial untuk dijadikan bahan utama pembuatan kompos. Kualitas bahan kompos menentukan laju dekomposisi bahan kompos. Dalam proses pengomposan sering ditambahkan dekomposer, sebagai agen untuk mempercepat proses dekomposisi. Tujuan percobaan pengomposan ini adalah untuk mempelajari pengaruh kotoran domba dan pengurai B8 terhadap kualitas kompos dari jerami padi, brangkasan jagung, dan batang pisang. Percobaan dilakukan di Kebun Percobaan Cikabayan IPB, Dramaga Bogor. Proses pengomposan dilakukan secara aerob. Seberat 15 kg bahan campuran jerami padi, brangkasan jagung dan batang pisang dengan perbandingan 2:2:1 digunakan untuk bahan utama pengomposan untuk setiap satuan percobaan. Perlakuan percobaan pengomposan meliputi kontrol (tanpa kotoran domba dan B8), standar (ditambah 3 kg kotoran domba, tanpa B8), D1 (tanpa kotoran domba, ditambah B8 25 ml), D2 (tanpa kotoran domba, ditambah B8 50 ml), DoD1 (ditambah 3 kg kotoran domba dan B8 25 ml), dan DoD2 (ditambah 3 kg kotoran domba dan B8 50 ml). Semua perlakuan ditambahkan 300 g urea, dibasahi, dibalik dan diaduk setiap 3 minggu. Tumpukan kompos dipertahankan lembabannya selama proses pengomposan. Pengamatan suhu kompos dilakukan setiap minggu mulai minggu ke-1 hingga minggu ke-12 dengan menancapkan termometer kompos ke dalam tumpukan kompos. Pengambilan contoh kompos dilakukan pada 0, 4, 8, dan 12 minggu pengomposan. Uji kualitas kompos didasarkan pada sifat kimiawi kompos yang meliputi kadar C-organik, N, dan S. Hasil percobaan menunjukkan bahwa perlakuan kotoran domba dan dekomposer B8 berpengaruh nyata terhadap kadar N, kadar S, nisbah C/N dan C/S, tetapi tidak berpengaruh nyata terhadap kadar C organik. Kualitas kompos terbaik ditemukan pada perlakuan DoD2 dengan nilai C-organik 29,9%, kadar N 1,9%, kadar S 1,2%, nisbah C/N 16,1, dan nisbah C/S 24,7, meskipun secara statistik perlakuan DoD2 dan DoD1 tidak berbeda nyata. Kata kunci : Nisbah C/N, dekomposisi, unsur hara, kompos, Organic matter affects the physical, chemical, and biological properties of the soil, therefore it can maintain soil function as a medium for plant growth. Rice straw, corn stover and banana stalks are potential agricultural waste to be used as the main material for composting. The quality of the compost material determines the rate of decomposition of the compost material. In the composting process, a decomposer is often added, as an agent to speed up the decomposition process. The purpose of this composting trial was to study the effect of sheep dung and decomposer B8 on the quality of compost from rice straw, corn stover, and banana stalks. The trial was carried out at the Cikabayan Experimental Station IPB, Dramaga Bogor. The composting process is carried out aerobically. A mixture of 15 kg of rice straw, corn stalk and banana stalks with a ratio of 2: 2: 1 is used for the main composting material for each trial unit. The trial treatments were Control (without sheep dung and B8), Standard (added 3kg sheep dung, without B8), D1 (without sheep dung but added B8 25 ml), D2 (without sheep dung but added B8 50 ml) , DoD1 (added 3 kg sheep dung
Keyword: C/N ratio, decomposition, nutrients, compost

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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