Judul: Penggunaan Pembenah Tanah untuk Perbaikan Sifat Tanah dan Budidaya Padi Gogo (Oryza sativa (L.) Merril) pada Pasir Tailing Tambang Timah
Abstrak: The green house experiments of ameliorant for soil improvement and nature cultivation of upland rice (Oryza sativa (L.) Merrill) at tin mine tailings area was conducted, in October 2010 - January 2011. The Research objectives are to evaluate the effect of mineral soil material , compost, and steel slag on (1) change in soil physical properties (2) the amount of percolation water, the levels leached water percolation of ammonium, phosphate, and potassium; (3) the uptake of N, P, K, Ca, Mg; (4) growth and yield of plants and (5) choose the best ameliorant composition for rehabilitation the tailings and upland rice cultivation. The treatment are T000, T011, T022, T 033, T101, T110, T112, T 113, T121, T122, T131, T 133, T202, T211, T212, T220, T221, T222, T223, T 232, T233, T303, T311, T 313, T322, T323, T330, T 331, T332, T333. The first numeral after T = soil mineral, second numeral = compost, and the third numeral = steel slag as soil ameliorant. They were arranged in a completely randomized design with three replications. The results showed that the soil ameliorant reduce bulk density, increasing the total pore space and available water capacity, and improve upland rice yields. Therefore, the amount of required ameliorant consists of mineral soil 70 ton ha-1, compost 15 ton ha-1 and 3 ton ha-1 steel slag.
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Judul: Pemberian Abu Volkan dan Kombinasinya dengan Slag untuk Peningkatan Pertumbuhan Tanaman Padi di Tanah Gambut
Abstrak: In Java, the rate of population growth increases while agricultural land decreases. The decrease of agricultural land are due to conversion. The decrease of agricultural land in Java must be substituted by other land. One of the land is peat soil. However, peat soil has low fertility. This is due to acid soil pH and low nutrient availability. One of the efforts to increase fertility of peat soil is application of ameliorants. The objectives of this research were to evaluate the effect of volcanic ash and its combination with slag to the changes of chemical properties of peat soil, rice growth, and the efficiency of N, P, and K absorption. The experiment was conducted in completely randomized design (CRD) with 4 replications. It consisted of standard treatment, control treatment, 3% volcanic ash, 6% volcanic ash, 9% volcanic ash, 5% volcanic ash without slag (0%), 1.25% slag + 3.75% volcanic ash, 2.5% slag + 2.5% volcanic ash, 3.75% slag + 1.25% volcanic ash, and 5% slag without volcanic ash (0%). The rice of variety that was used namely Ciherang. The results showed that the combination treatment of 3.75% slag + 1.25% volcanic ash increased soil pH of peat soil, exchangeable of Ca and Mg, N-total and available P in peat soil. The combination treatment of 3.75% slag + 1.25% volcanic ash also increased the rice growth. Those values were higher significantly than those of single treatment of volcanic ash, standard treatment, and control treatment. In addition, the combination treatment of 3.75% slag + 1.25% volcanic ash significantly increased the plant uptake of N, P, K, Ca, Mg, and Si. The combination treatment of 3.75% slag + 1.25% volcanic ash increased the efficiency of N, P, and K absorption. Those values were higher than those of single treatment of volcanic ash and standard treatment. The combination treatment of 3.75% slag + 1.25% volcanic ash was the best treatment as ameliorant for improving the fertility of peat soil, increasing rice growth and increasing the efficiency of N, P, and K absorption.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular