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: Pengaruh terak baja terhadap sifat kimia tanah serta pertumbuhan dan produksi tanaman Padi (Oryza Sativa) pada tanah gambut dalam dari Kumpeh, Jambi
Abstrak: Serious efforts to achieve self sufficiency in rice to fullfil consumption of population growth in Indonesia become very important. One of the most important problems was the decrease of fertile land in Java along with significant numbers of land conversion to nonagricultural usage. One of the important effort to overcome this problem was utilizing peatlands outside Java. Utilizing of peatland for rice cultivation faces many problems such as soil acidity and toxicity of organic acid which effect to crop growth. Steel slag is a by-product furnace in the process of steel manufacturing. These materials can be used as liming material for improving chemical properties of peat soil. This research purposed to evaluate effect of steel slag on chemical properties of soils and also rice growth and yield. Research was carried out of pot experiment in greenhouse by using peat soils from Kumpeh, Jambi. Slags were applied in dosage 0, 1, 2, 3, 4, and 5% or 0, 30, 60, 90, 120, and 150 g / pot, combined with NPK fertilizer in dosage 50 and 75% from standard, compared with control and standard. The result shows that steel slag significantly improved chemical properties of soils such as raised soil pH, exchangeable Ca and Mg, and available Mn in soils. Toxic heavy metal in rice and soils were given by NPK fertilizer treatment. Steel slag also significantly increased rice yield and growth, reduced unfilled spikelets, and also increased nutrient rate of Ca and Mg in crop. In addition, steel slag reduced usage of conventional fertilizer. This was shown by higher value of fertilizer efficiency on steel slag treatment.
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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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