Judul: Penerapan Teknik Konservasi Tanah dan Air Dalam Meningkatkan Produksi Kelapa Sawit.
Abstrak: Indonesia region like Lampung is less suitable for oil palm plantation, because of long dry season and low rainfall. One of the effort to solve the drought is application of soil and water conservation technique such a ridge terrace and silt pit. This research was aimed to study effectiveness of ridge terrace and silt pit treatment which were accomplished with “biopori” and vertical mulches on soil moisture content as well as growth and production of oil palm plantation; to study the correlation of soil moisture content and growth and production of oil palm. The research was conducted in Afdeling III, Rejosari Management Unit PT Perkebunan Nusantara VII, South Lampung. The area of research consisted of 3 blocks namely block 1 (375) with ridge terraces treatment, block 2 (415) with no treatment, and block 3 (414) with silt pits treatment. The research results show that application of conservation techniques were able to increase monthly of average soil moisture content where in the figure in block 1, block 3, and block 2 are 48.32%, 45.21%, and 43.64%, respectively. The appearance of frond fracture of the three blocks is not significantly different. The production of oil palm in block 1 (ridge terraces) and block 3 (silt pits) are higher than block 2 (control). The production of block 1, 2, and 3 are 25 343.18, 22 677.38, and 24 251.97 kg/ha/year, respectively. Correlation value of soil moisture content towards oil palm production are very low. The correlation of block 1 is 0.175, block 2 is 0.100, and block 3 is 0.059. Correlation value of number ripe fresh fruit bunches and female infloresence nine months before on block 1, 2, and 3 are 0.628, 0.230, and 0.539, respectively.
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Judul: Pengaruh Perlakuan Teknik Konservasi Air terhadap Evapotranspirasi Tanaman Kelapa Sawit (Studi kasus : PT. Sawit Asahan Indah, Rokan Hulu, Riau)
Abstrak: Water conservation by form of rorak (silt pit) is one of rainwater harvesting methods that can be applied in palm oil plantation to fulfill plants water requirements. Installation of rorak can increase surface water utilization and irrigation water use efficiency. This study aimed to analyze the effect of water conservation technique on soil water content and evapotranspiration of palm oil plantations. This research was conducted by measuring the soil water content in experimental blocks (7, 8, and 18) and control blocks (6, 16, and 17). Twenty five set soil moisture sensor devices were planted on each block. Soil water content was calculated by using soil water content calibration curves obtained through previous research. Evapotranspiration was calculated by using water balance approach in palm oil plantation. As the results, the level of soil water content and evapotranspiration in experimental blocks was higher than the control blocks. Daily average evapotranspiration in experimental and control blocks respectively were 3.9 mm and 3.7 mm. The values of water storage in experimental blocks except block 7 were greater than the water storage in control blocks.
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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.
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