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: Pengaruh Pupuk Mikro-Biostimulant Cair dan Bahan Organik terhadap Pertumbuhan dan Serapan N, P dan K Tanaman Caisim (Brassica juncea) pada Latosol (Oxic Dystrudept), Darmaga
Abstrak: Latosol fertilty is generally low because of its organic content and lack of nutrient availability. One way to overcome its fertility was to used some fertilizer, both organic and inorganic fertilizers. Fertilizer can be applied to the soil and plants. Fertilizers by plants typically use a liquid fertilizer that is expected can overcome the deficiencies of nutrients and effectiveness of absorption. Sufficient nutrients and balance of plant are necessary. Plants can growth well when they have good support from condition and nature of soil so plants can used nutrients to its full potential. Nutrients needed by plants consist of macro elements (C, H, O, N, P, K, Ca, Mg, and S) and micro elements (Fe, Mn, Mo, B, Cu, Zn, and Cl). If all of the elements were not met, plants would growth abnormal. Micro nutrients needed in smaller amounts than fertilizer macro, but its presence is very important, for example in plant metabolic reactions, especially associated with the activity of the enzyme. Maximum growth and production can be ensured by maintain the amount of macro and micro nutrient status. One way to overcome micro-nutrient deficiencies are generally carried out through the leaves. The purpose of this research was to study the effect of Fertilizer Micro-Liquid Biostimulant and organic matter on growth and N, P and K uptake by Chinese Mustard (Brassica juncea) var. Tosakan in Latosol, Darmaga. The research arranged according to Completely Randomized trial using factorial design of two-factor repeated 5 times. The first factor was the Micro-Biostimulant Liquid Fertilizer (MBC) consisting of 4 levels, ie, MBC-0%, MBC-50%, MBC-100% and MBC-150%. The second factor was an organic matter consist of three doses, ie, without organic matter, 2.5 tons/ha of organic matter and 5.0 tons / ha of organic matter. The results showed that MBC treatment equivalent to 100% recommended doses provide the highest results for fresh weight and plant uptake of N, P and K. Aplication of MBC 100% significantly increased the fresh weight by 21% and nutrient uptake of N 27%, P 29% and K 20% compared with MBC 0%. The application of organic matter (cow manure) 5 ton/ha gave the highest results of the fresh weight and nutrient uptake of N, P and K. The treatment was significantly increased the fresh weight by 24% and nutrient uptake of N 23%, P 24% and K 25% compared with without organic matter. There was no interaction between MBC treatment and application of organic matter for all parameters.
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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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