Judul: Responses in Growth and Production of Sweet Corn on the Application of Coal fly Ash in Inceptisol of Dramaga
Abstrak: Penghapusan Fly Ash Bottom Ash (FABA) dari daftar limbah B3 (bahan berbahaya dan beracun) di Indonesia memungkinkan pemanfaatannya dikembangkan di bidang pertanian. Selain SiO2, Al2O3, dan Fe2O3, FABA juga mengandung K, Na, Ca, Mg, Fe, Cu, Zn, dan Mn, sehingga berpotensi untuk dimanfaatkan sebagai amelioran tanah dan pupuk anorganik, terutama sebagai sumber Si. Penelitian ini bertujuan mengevaluasi efektivitas aplikasi fly ash batu bara terhadap pertumbuhan dan produksi jagung manis (Zea mays saccharata Strurt.) pada Inceptisol Dramaga. Percobaan ini menggunakan RAK dengan perlakuan fly ash batu bara (FA) 6 taraf yang terdiri dari kontrol (tanpa pupuk NPK dan FA), 0%, 50%, 100%, 150%, dan 200% FA dengan 4 ulangan sehingga diperoleh 24 satuan percobaan. Pupuk kandang dan pupuk N, P, dan K diaplikasikan pada seluruh petak percobaan dengan dosis yang sama. Analisis data meliputi ANOVA, DMRT, dan Relative Agronomic Effectiveness (RAE). Hasil penelitian ini menunjukkan bahwa aplikasi FA berpengaruh sangat nyata terhadap tinggi dan produksi tanaman, ketahanan terhadap serangan OPT, Si tersedia, dan serapan Si. Semua taraf perlakuan terbukti efektif dengan nilai RAE ≥100%. Taraf perlakuan 200% FA atau setara dengan 10 ton FA/ha ditetapkan sebagai dosis rekomendasi., The elimination of Fly Ash Bottom Ash (FABA) from the Indonesian list of hazardous wastes allows its utilization to be expanded for agriculture purposes. Besides SiO₂, Al₂O₃, and Fe₂O₃, FABA also contains K, Na, Ca, Mg, Fe, Cu, Zn, and Mn, so that it could be potentially used as soil ameliorant and inorganic fertilizer, particularly as Si source. This study aimed to evaluate the effectiveness of coal fly ash application on the growth and production of sweet corn (Zea mays saccharata Sturt.) in Inceptisol of Dramaga. This experiment applied RCBD with coal fly ash (FA) treatment of 6 levels consisting of control (without NPK fertilizers and FA), 0%, 50%, 100%, 150%, and 200% FA with 4 replications resulted in 24 experimental units. Manure and N, P, K fertilizers were applied at the same dose to all of the experiment plots. Data were analyzed for ANOVA, DMRT, and Relative Agronomic Effectiveness (RAE). The results showed that FA apllication was very significantly increasing the height and production of sweet corn, resistance to pest and disease attack, available Si, and Si absorbtion. All treatment levels were found effective with RAE value of ≥100%. The treatment of 200% FA equals to 10 ton FA/ha is considered as the recommended dose.
Keyword: RAE, Si fertilizer, ameliorant, Zea mays

Judul: Interaction of Fly Ash, Calcite Residue, and Compost Residue for Improvement of Some Chemical Properties of Podsolic Soil and Growth of Sorghum (Sorghum bicolor L. Moench)
Abstrak: Proses produksi PLTU yang menggunakan batubara sebagai sumber energi pembakarannya menghasilkan limbah padat berupa fly ash (FA). Limbah FA berpotensi dimanfaatkan untuk perbaikan sifat kimia tanah dan pertumbuhan tanaman. Penelitian ini bertujuan untuk menguji pengaruh pemberian kedua FA serta interaksinya dengan residu kompos dan kapur terhadap perubahan sifat kimia tanah Podsolik dan pertumbuhan sorgum. Percobaan menggunakan rancangan acak lengkap faktorial dengan 3 faktor yaitu FA (5 taraf: 0, 2, 4, 6, dan 8 ton/ha), residu kompos (3 taraf: 0, 10, dan 20 ton/ha), dan residu kapur (2 taraf: 0 dan kapur dengan dosis 1x Al-dd). Parameter yang diamati mencakup pH, Al-dd (dapat dipertukarkan), P-tersedia, Ca-dd, Mg-dd, K-dd, kapasitas tukar kation (KTK), kejenuhan basa (KB), C Organik, serta pertumbuhan tanaman yaitu tinggi dan bobot tanaman. Hasil percobaan menunjukkan bahwa pemberian kedua FA secara tunggal, sama seperti pemberian pertama, tidak berpengaruh nyata terhadap semua parameter yang diamati. Pemberian FA berpengaruh nyata jika diinteraksikan dengan residu kapur dan kompos. Adanya residu kapur mampu memperbaiki sifat kimia tanah berupa pH, Al-dd, Ca-dd, serta Mg-dd tanah, dan pertumbuhan sorgum., The production process of electric steam power plant that uses coal as its combustion energy, produces waste in the form of fly ash (FA). FA waste has the potential to be utilized to enhance the chemistry of soil and plant growth. This study aimed to examine the effect of the application of both FA and its interaction with compost and calcite residues on changes in the chemical properties of Podsolic soil and the growth of sorghum. The experiment used a factorial, completely randomized design with three factors, FA (5 levels: 0, 2, 4, 6, and 8 tons/ha), compost residue (3 levels: 0, 10, and 20 tons/ha), and calcite residue (2 levels: 0 and calcite with a dose of 1x exchangeable-Al). The parameters observed included pH, exchangeable-Al, P-availability, exchangeable cations, cation exchange capacity (CEC), base saturation, Organic-C, and plant growth as height and weight. The experimental results showed that the second treatment of a single dose of FA has no significant effect on all parameters. The addition of FA significantly impacted when interacting with calcite and compost residues. Calcite residue enhanced the soil's chemical qualities, including pH, exchangeable (Al, Ca, Mg) of soil, and the growth of sorghum.
Keyword: ameliorant, coal, coal waste, liming

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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