Judul: Perbaikan lahan bekas tambang pasir besi dengan aplikasi bahan humat dan kapur untuk tanaman semangka (Citrullus vulgaris scard)
Abstrak: Activities in iron sand mining affects the degradation of physical and chemical properties of soils. Several soil problems of ex-mined land of iron sand mining are low nutrient availability, low available soil water, high soil temperature, porous structure and uneven topography. Improvement of the such soil needs application of appropriate soil ameliorants such as humic substance and lime. It has been known that humic substance can be obtained by extracting organic matter, therefore, application of that material may improve the chemical, physical, dan biological properties of soil. The purpose of this research is to examine the effect of humic substance and lime application on ex-mined land of iron sand mining on soil characteristics, growth, and production of watermelon. The research was conducted in ex-mined land of iron sand quarry of PT. Antam (Aneka Tambang) at Patutrejo, Grabag village, Purworejo, Central Java from March 2010 until March 2011. The field research used Split Plot of Complitely Randomized Design consisted of two factors: Humic substance (H0: 0; H1: 7.5; H2:15; and H3: 22.5 L/Ha) and Lime (K: 0 and K1:100 kg/Ha) with three replications. The parameters of growth and production (shoots length, leaf number, segment number, male flowers number and fruit weight) were measured to determine the effect of the treatments. The chemical properties of soils were analyzed for monitoring the soil properties changes. The results showed that humic substance and lime application increased the availability of P, K, Ca, and Mg. Humic substance has carboxil and fenolic clusters those have capability to bound Al and Fe ions from soil solution for forming low solubility of complex compounds. Therefore, the concentration of free Al and Fe ions in the solution will decrease causing the available of phosphate increase. Humic substance increased the shoot length, leaf number, male flowers number, and the segment number. The application of humic substance as much as 22.5 L/Ha increase the watermelon production by 28% from 6.15 ton/Ha at K0H0 to 7.88 ton/Ha at K0H3 treatment. Leaf spot disease, soft rot, and pest snails affected growth and yield of watermelon.
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Judul: Reklamasi lahan bekas tambang pasir besi dengan aplikasi bahan organik in situ serta penambahan bahan humat dan kapur pada tanaman kacang tanah (Arachis hypogaea l), studi kasus PT. Aneka Tambang, Kecamatan Kutoarjo, Kabupaten Purworejo, Jawa Tengah
Abstrak: Mining activity is an effort that cannot be separated from the modern civilization. The activity of iron sand mining made that area degraded in soil physical and chemical properties. The research was conducted in iron sand post mining area of PT. Aneka Tambang (ANTAM), at Patutrejo, Grabag Village, Kutoarjo, Central Java from March 2010 until July 2010. Reclamation efforts had been conducted by PT. ANTAM by giving compost to the soil and then planting perenial plants namely Ketapang tree. That compost was imported from others area. This became an obstacle because compost in the surrounding area was very limited. Therefore using organic matter in situ, was a simple and easy way. In situ biomass production needed to be developed to improve soil fertility of iron sand post mining area. Therefore, it was needed plants that were tolerant to soil physical properties in ex-mining area, as well as producing organic matter in situ. The plant that have been used often as organic matter source in situ was legume crops. Legume crops can produce more organic matter, high in nutrient uptake and have nodules that can fixed nitrogen from atmosphere. Legume crop that was used in this research was peanut (Arachis hypogaea L). Planting peanut in iron sand mining area may improve soil properties through nitrogen (N2) fixation.
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Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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