Judul: Pengelolaan Lahan Gambut di Perkebunan Kelapa Sawit di Kebun Teluk Bakau, PT Bhumireksa Nusa Sejati, Minamas Plantation, Riau
Abstrak: Internship was conducted at the Teluk Bakau Estate, PT Bhumireksa Nusa Sejati (BNS), Riau in order to follow the practise of the company in managing peatland for oil palm crop, as well as to study the water management system of estates. Activity was carried out for 4 months from February to June 2013. Target of water level at PT BNS plantation commonly is in range 25 to 50 cm below the ground surface. Drainage system in PT BNS consists of main canals, branch canals, new branch canals, collection canals, collection trenches, middle trenches, and field drain. The efforts to maintaining the water level are building up water zoning, installing piezzometers, water gates, over flow gates, water flows, building up emergency gates, installing spillway, treating canals, and making maps and standard operational procedure of water management system. Simple linear regression analysis was used to estimate the effect of rainfall to water level. Result showed that the rainfall significantly (p value = 0.014) affected the water level. Increasing 1% of the rainfall would increase the water level by 0.06899% below the ground surface. Multiple linear regression analysis was used to estimated the effect of rainfall and water level to production. Results showed that the rainfall and the water level did not affect the production. Most of the water levels at Teluk Bakau Estate are controlled well. Most of the drainage system conditions are good and can be passed by conveyance of water. Water management system is managed well.
Keyword: water management, water level, Riau, drainage

Judul: Pengelolaan Air Kebun Kelapa Sawit (Elaeis Guineensis Jacq.) pada Lahan Gambut, Teluk Bakau Estate, PT Bhumireksa Nusa Sejati, Minamas Plantation, Riau
Abstrak: Kegiatan magang dilaksanakan di kebun Teluk Bakau Estate, PT Bhumireksa Nusa Sejati (BNS), Riau dengan tujuan umum yakni untuk mempelajari kegiatan on farm di perkebunan kelapa sawit lahan gambut serta dapat bekerja nyata untuk perusahaan dan tujuan khusus mempelajari pengelolaan air kebun kelapa sawit lahan gambut. Kegiatan dilakukan selama empat bulan mulai Februari – Juni 2015. Pengelolaan air (Water management) di TBE berupaya mempertahankan level air pada kisaran -30 sampai -50 cm di bawah permukaan tanah (dpt) yang dimaksudkan untuk konservasi tanah gambut, kelancaran transportasi kebun dan produksi yang berkelanjutan. Sistem drainase kebun terdiri atas kanal utama, kanal cabang, kanal cabang baru, kanal kolektor, parit tengah dan field drain. Analisis regresi linier sederhana digunakan untuk melihat pengaruh curah hujan terhadap level air dan pengaruh level air terhadap produksi TBS. Kajian menunjukan bahwa curah hujan berpengaruh nyata (P value = 0.021) terhadap level air, kenaikan 1 mm curah hujan akan menaikan level air sebesar 0.0982 cm dpt. Begitu juga dengan level air yang berpengaruh nyata terhadap produksi TBS. Secara keseluruhan kegiatan pengelolaan air di TBE sudah dilaksanakan dengan baik, level air terjaga, saluran drainase cukup baik dan dapat dilewati transportasi air.
Keyword: level air, produksi, transportasi, pengelolaan air

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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