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 Trass dan Kombinasinya dengan Abu Volkan terhadap Sifat Kimia Tanah dan Pertumbuhan Padi pada Tanah Gambut dari Kumpeh, Jambi
Abstrak: Nowadays in Indonesia, the problem of food crisis is still happening, due to increasing of population annually, needs to increase food availability. On the other hand, the productive land for agriculture have limitations because the large land conversion to non-agricultural land. The use of marginal land such as peat is an attempt to overcome the limited productive land for growing rice. Peat soils have low soil fertility level and acid soil reaction in nature. The conditions of peat soils require amelioration to improve soil fertility. The ameliorants that have potential to increase soil fertility are trass and volcanic ash. The purpose of this research was to examine the effects of trass and its combination with volcanic ash on soil chemical properties and rice growth. The research was conducted in a pot experiment using peat soils from Kumpeh, Jambi. Doses of trass as a single factor treatment were 0, 3, 6, and 9% or 0, 90, 180, and 270 gram/pot, and doses of the combination treatments between trass and volcanic ash were 0+7.5, 1.875+5.625, 3.75+3.75, 5.625+1.875, and 7.5+0% or 0+225, 56.25+168.75, 112.5+112.5, 168.75+56.25, and 225+0 grams/pot, the all treatments compared to standard fertilization. The research design was used Completely Randomized Design (CRD). The results showed that giving the trass as a single factor significantly increased the soil pH, Exchangable Al and Mg, available Zn and Mn, plant height, productive tillers, plant biomass, uptake of K, Si, and plant Zn. The combination trass with volcanic ash significantly increased the soil pH, Exchangable Al, total-N, Exchangable Na, available Zn and Mn, plant height, productive tillers, plant biomass, uptake of P, K, Si, and plant Zn. Beside that, combination trass with volcanic ash significantly improved the efficiency of P and K fertilization
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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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