Judul: The Effect Of Fertilization On The Abundance And Composition Of Soil Macroinvertebrates On Mustard (Brassica rapa L.) Plantations
Abstrak: Caisim (Brassica rapa L.) merupakan tanaman yang bernilai ekonomi bagi manusia. Pemberian pupuk memengaruhi produktivitas tanaman dan komposisi fauna tanah. Penelitian ini bertujuan menganalisis pengaruh pemberian pupuk terhadap kelimpahan dan keanekaragaman makroinvertebrata tanah. Plot penanaman diberi perlakuan dengan pupuk yang berbeda. Pengambilan sampel makroinvertebrata dilakukan dengan metode hand sorting dan pitfall trap yang dilakukan selama tiga periode yaitu sebelum penanaman, ketika penanaman dan setelah tanaman dipanen. Pitfall trap digunakan pada saat periode masa tanam, sedangkan pada periode sebelum penanaman dan setelah tanaman dipanen digunakan metode hand sorting. Hasil penelitian dikoleksi 699 individu dari 16 famili dan 20 morfospesies. Keanekaragaman makroinvertebrata tanah tertinggi ditemukan pada periode setelah tanaman dipanen. Jumlah individu terbanyak ditemukan pada kontrol, diikuti pada tanaman yang diberikan pupuk organik dan individu terendah ditemukan pada perlakuan pupuk NPK., Mustard (Brassica rapa L.) has an economical important for humans. Fertilizer application affects plant productivity and soil fauna composition. This study aims to analyze the effect of fertilizer application on the abundance and diversity of soil macroinvertebrates. The planting plots were treated with different fertilizers. Sampling was carried out by hand sorting and pitfall trap methods in three periods, i.e., before planting, during planting and after the plants were harvested. Pitfall traps were used during the planting period, while in the period before planting and after harvested was used hand sorting method. Results showed 699 individuals belong to 16 families and 20 species were collected. The highest diversity of soil macroinvertebrates was found in the period after harvested. The highest number of individuals was found in the control, followed by the plots with organic fertilizer and the NPK fertilizer treatment.
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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: 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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