Judul: Manure Application for Improvement of Soil Biological Properties and Growth of Kale (Ipomoea reptans Poir)
Abstrak: Alternatif pemupukan dengan menggunakan pupuk kandang saat ini perlu dilakukan karena pupuk anorganik saat ini yang mahal dan dapat menyebabkan dampak negatif terhadap lingkungan jika digunakan secara terus menerus. Selain dapat memperbaiki sifat kimia tanah, pupuk kandang juga dapat memperbaiki sifat-sifat biologi tanah seperti menyumbangkan organisme tanah yang dapat membantu mempercepat proses dekomposisi bahan organik dan ketersediaan hara bagi tanaman. Tujuan dari penelitian ini yaitu menguji kandungan dan pengaruh dari pupuk kandang sapi, kambing, dan domba terhadap sifat biologi tanah untuk pertumbuhan kangkung. Metode yang digunakan untuk menganalisis total mikrob dan fungi yaitu Total Plate Count (TPC) dan fauna tanah diekstrak dengan metode Berlese Funnel Extractor. Hasil penelitian menunjukan berdasarkan parameter yang dianalisis, kandungan pada pupuk kandang sudah memenuhi standar mutu, namun untuk total hara makro pada pupuk kandang kambing masih di standar karena nilainya kurang dari 2%. Perlakuan dengan pemberian pupuk kandang (sapi, kambing, dan domba) memiliki pengaruh yang nyata lebih tinggi dibandingkan perlakuan kontrol dan pupuk majemuk NPK terhadap total mikrob, fungi, fauna tanah dan pertumbuhan kangkung. Secara umum, pupuk kandang yang paling baik yaitu pupuk kandang domba karena memiliki pengaruh yang nyata terhadap sifat biologi tanah dan dapat menghasilkan pertumbuhan kangkung yang lebih unggul dibandingkan perlakuan lainnya., Alternative fertilization using manure currently needs to be done because inorganic fertilizers are currently expensive and can cause negative impacts on the environment if used continuously. Besides being able to improve soil chemistry, manure can also improve soil biological properties such as donating soil organisms that can help accelerate the process of decomposition of organic matter and nutrient availability for plants. The purpose of this study was to examine the effect of cow, goat, and sheep manure on the biological properties of soil for the growth of kale plants. The method used to analyze the total microbes and fungi, namely Total Plate Count (TPC) and soil fauna, was extracted by the Berlese Funnel Extractor method. The results showed that based on the parameters analyzed, the content of manure met quality standards, but the total macronutrients in goat manure were still standardized because the value was less than 2%. Treatment with manure (cows, goats, and sheep) has a significantly higher effect than control treatment and NPK compound fertilizer on total microbes, fungi, soil fauna and kale growth. In general, the best manure is sheep manure because it has a significant influence on the biological properties of the soil and can produce kale growth that is superior to other treatments.
Keyword: bahan organik, dekomposisi, fauna tanah, fungi, mikrob

Judul: The Quality of Liquid Organic Fertilizer from a Combination of Dairy Cow Manure and Laying Hen on Production of Kangkong
Abstrak: Kotoran sapi perah dan ayam petelur merupakan bahan organik yang dapat dimanfaatkan menjadi pupuk organik cair (POC). Pupuk organik cair mengandung unsur hara yaitu nitrogen, fosfor, dan kalium yang dapat menunjang pertumbuhan, perkembangan, dan kesehatan tanaman. Penelitian ini bertujuan untuk menganalisis kadar hara makro yang dihasilkan dari POC berbahan dasar kotoran sapi perah dan ayam petelur, serta menguji efektivitasnya terhadap produktivitas tanaman kangkung darat (Ipomea reptans Poir.). Tahapan yang pertama yaitu pembuatan POC dengan 3 perlakuan meliputi 100% kotoran sapi perah (S100A0), 80% kotoran sapi perah dan 20% kotoran ayam petelur (S80A20), 60% kotoran sapi perah dan 40% kotoran ayam petelur (S60A40) data di olah secara deskriptif. Tahap kedua pengujian pada tanaman kangkung dengan 3 perlakuan yaitu kontrol, NPK, POC NPK, analisis data menggunakan rancangan acak lengkap (RAL). Hasil penelitian menunjukkan bahwa perlakuan S60A40 memiliki kandungan NPK tertinggi dibandingkan perlakuan lainnya, namun belum memenuhi standar. Uji tanam menunjukkan bahwa peran POC belum dapat memberikan hasil yang optimal dalam meningkatkan produktivitas kangkung darat., Cow and layer chicken manure are organic materials that can be utilized to produce liquid organic fertilizer (POC). Liquid organic fertilizer contains essential nutrients such as nitrogen, phosphorus, and potassium, which support plant growth, development, and health. This study aims to analyze the macro nutrient content produced from POC based on cow and layer chicken manure and to test its effectiveness on the productivity of kangkong (Ipomea reptans Poir.). The first stage involves the production of POC with three treatments: 100% cow manure (S100A0), 80% cow manure and 20% chicken manure (S80A20), and 60% cow manure and 40% chicken manure (S60A40). The data are processed descriptively. The second stage is the testing of kangkong using a Completely Randomized Design with three treatments: control, NPK, and POC NPK, and data analysis using a completely randomized design (CRD). The results indicate that the S60A40 treatment has the highest NPK content compared to other treatments, although it does not yet meet the standard. The planting test indicated that the POC treatment did not provide optimal result in increasing the productivity of kangkong.
Keyword: Ipomea reptans Poir, kotoran ayam petelur, kotoran sapi perah, pupuk organik cair

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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