Judul: Determination of Nutrient Range Adequancy Nutrient On Oil Palm Plantation (Elais gueneensis) Generate
Abstrak: The agricultural commodity was one of the mainstays as an effort to increase the Country's foreign exchange apart from the sector of oil and gas. One of the priority for the development were oil palm. The problem that emerged the oil palm plantation was the determination of the dosage of fertilization that was not yet optimum. To achieve the optimum fertilization recommendation was determined by the value of the crop nutrient. One of the methods of knowing the status of the crop nutrient that is through the analysis of the crop, the interpretation used the critical value or the range of the adequancy of the nutrient. This research was aimed to determine criteria the value of the crop nutrient was based on the range of the adequancy of the nutrient to the oil palm (Elaeis guineensis) for the crop produced. This research was used the survey method, that is taking the sample of the oil palm crop randomized to plantations that spread in Riau, Lampung, West Kalimantan, Central Kalimantan and South Sumatra. The sample of the crop came from a pair of leaf to the tail of the lizard from the 17th steam. Then was taken by a third to the middle and was removed palm leaf rib. Samples of these leaves were gathered from 20 trees. The level of nutrient was produced by the analysis of the crop were connected with the growth variabel and the production to determine the range of the adequancy of the nutrient. The election of the production variable showed that the FFB production better than the average janjang weight. Based on the theory of the range of the adequancy of the nutrient that the distribution of the point that more focuss and conical above had the value of the good adequancy of the range, so as the range variable of the adequacy of the nutrient was based on the production of FFB. Results adequacy burly range determination are as follows; N ranged from 1:41 to 2.53, P elements ranged from 0:08 until 0:18, K elements ranged from 0.86 to 1:26, the elements Ca ranged from 0.85 to 0:42, Mg ranged from 0:16 to 0:41, the elements around Cu from 4.1 to 26.2 and for the elements Zn ranged from 21.67 to 45.65. Results showed that the interpretation of N and Mg in are in less level, while the elements P, K, Ca and Zn are in the current status and the status of level Cu is high.
Keyword: 

Judul: Model of nutrients balance related to oil palm (Elaeis guineensis Jacq) productivity
Abstrak: Indonesia is the country which has the largest area of oil palm plantation in the world. Indonesia had only about 1.12 million hectares of oil palm plantation in 1990s, but greatly increased in 2000s which attain 4.15 million hectares and in 2012 had reached about 9.07 million hectares. Oil palm has many advantages compared to other oil crops such as higher production per unit area, long economic life, and its product, either edible or nonedible one can be used in variety industries. Oil palm productivity is highly affected by so many internal and external factors. Fertilization is one of the external factors which have a big effect on oil palm productivity. Nutritients addition through fertilization will lead of alter nutrient balance in the soil; which will affect nutrients availability and plant nutrient uptake. The aim of this study was to determine the nutrients balance for oil palm both of in the plant tissue and the soil. Hopefully, the results of the study could be use on of consideration in fertilizer recommendation practice related to determination of fertilizer requirements for oil palm thus will be more appropriate in order to achieve optimum oil palm productivity. Exploration survey method was used in this study by collecting data of oil palm production, foliar and soil analysis. The data were collected from several oil palm plantations in Indonesia such as North Sumatera, Jambi, Riau, West Sumatera, Lampung, South Sumatera, West Java, West Kalimantan, East Kalimantan, and South Kalimantan provinces. Diagnosis and Recommendation Integrated System (DRIS) was used for determined nutrients balance in the oil palm tissue whereas boundary line method was used for determining nutrients balance in the soil. The results showed that (1) the norms value for each nutrient ratio were 15.92 for N/P, 2.53 for N/K, 3.87 for N/Ca, 10.12 for N/Mg, 6.35 for K/P, 4.17 for Ca/P, 1.62 for Mg/P, 1.55 for K/Ca, 4.05 for K/Mg, and 2.65 for Ca/Mg; and (2) the optimum value of soil nutrient balance of Ca/K, Ca/Mg, and Mg/K were 6.4, 2.5, and 2.3 respectively.
Keyword: Nutrients balance, Boundary line method, DRIS, Elaeis guineensis Jacq

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
Keyword: