Judul: Pengaruh Residu Terakbaja Dan Fosfat Alam Terhadap Pertumbuhan Dan Serapan Hara Tanaman Jagung Pada Tanah Sulfat Masam Delta Telang Musi-Banyuasin Sumatera Selatan
Abstrak: Oxidized pyrite increases the availability of AI, Fe, and sulphate, and decreases the availability of phosphate and pH. This research was aimed to study the effect of basic slag and rock phosphate residue to the growth and nutrient uptake of com on acid sulphate soils Delta Telang Must Banyuasin, South Sumatera. This experiment design was factorial completely randomized design with 20 treatments residue, with 3 replicates, so there were 60 experimental units residue. The rate of basic slag residue applications were 0, 10, 20, 30, and 40 tonlha and rock phosphate residue were 4 levels namely 0, 1, 2, and 3 tonlha. The result of this research showed that without treatments basic slag and rock phosphate residue the plant growth slowly. It maybe because of extremely acid pH and increases availability of Al, Fe, and S04 =. Rock phosphate residue had not significant effect to the growth of plant and plant dry weight but basic slag residue had significant effect increasing rate of both parameters above. Basic slag residue applications of dosage 30 tonneslha increased plant dry weight, which was 0.595 g/polybag. Basic slag had significant effect decreasing concentrations of Mg, P, and Fe. Rock phosphate had significant effect decreasing concentrations of Mg. Interactions between basic slag and rock phosphate residue had significant effect decreasing concentrations of Mg, P, and Fe.
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Judul: Pengaruh Pemberian Fosfat Alam Terhadap Perubahan Sifat Kimia Tanah, dan Kadar Hara Pada Tanaman Jagung (Zea mays)
Abstrak: The utilization of acid soil for agriculture faced several obstacles, including P deficient. It is because P ions sorbed by various soil components, such as Fe-Al ions, and Fe-Al hydrous oxides. One of the efforts made to overcome this problem is the use of natural phosphate in acid soils. This study aims to determine the effect of natural phosphate fertilizers in soil chemical properties and nutrients rate in plant of Latosol (Oxyc Dystrudept) Darmaga. Experimental design used in this study was a randomized design with a single factor, named P fertilizer. Source of P fertilizer used in this study is a natural phosphate and SP-36. Treatment dosage of P fertilizer are, control I (0%), control II (N + K), Std 100% (N+K+SP36), RP 50%, RP 100%, RP 150%, RP 200%, (N + K 50%) + RP 50%, and (N + K 50%) + RP 100%. The results showed that the phosphate fertilizer did not significantly affect soil pH, exchangeable-Al, available-P, exchangeable-Ca, and exchangeable-Mg. phosphate fertilizer have significantly affect only in exchangeable-K. Meanwhile, phosphate not significantly affect the rate of Mg, K, Ca, P and N. Rock phosphate’s application significantly affected the growth of maize on 4 week after planting (MST) and 6 MST. Rock phosphate’s application did differ significantly on increasing cob with husk’s weight and cob without husk’s weight. But rock phosphate’s application did not differ significantly on total weight of stover. The highest percent of crop value in treatment who give rock phosphate fertilizer there is in treatment of RP 150% with 158.1%, and the lowest percent of crop value there is in treatment of (N+K 50%) + RP 50% with 98.6%, and lowest in all treatment there in treatment of Control I with 74.7%. From result of crop value can get a conclusion that rock phosphate fertilizer is better than standard fertilizer (SP36).
Keyword: acid soil, maize, phosphate

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf