Judul: Effect of Water Conservation Techniques on Water Availbility in The Palm Oil Plantations. (Case Study : PT. SAWIT ASAHAN INDAH, Rokan Hulu, Riau).
Abstrak: Ketersediaan air merupakan salah satu faktor pembatas utama bagi pertumbuhan dan produksi tanaman kelapa sawit. Teknik konservasi air merupakan salah satu upaya yang digunakan untuk mengantisipasi dan menanggulangi dampak kekeringan pada saat sebelum, selama dan setelah musim hujan agar curah hujan dapat diserapkan secara maksimal ke dalam tanah. Penelitian ini dilakukan untuk mengetahui pengaruh teknik konservasi air dalam meningkatkan ketersediaan air di perkebunan kelapa sawit dengan cara pengukuran kadar air tanah pada blok perlakuan dan blok kontrol di perkebunan kelapa sawit menggunakan sensor kadar air tanah. Teknik konservasi air berupa rorak di perkebunan kelapa sawit memberikan pengaruh untuk meningkatkan ketersediaan air dan kemampuan tanah dalam menyimpan air lebih lama. Kadar air tanah rata-rata pada blok perlakuan lebih besar daripada blok kontrol, yaitu masing-masing sebesar 15.3 dan 6.4% volume pada kedalaman 0 cm – 100 cm, 25.9 dan 7.5% volume pada kedalaman 100 cm - 200 cm.
Keyword: 

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.
Keyword: 

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
Keyword: