Judul: Studi pemanfaatan asam humat hasil ekstrasi dari andosol dan gambut dalam pertumbuhan semaian padi (Oryza sativa L.)
Abstrak: Asam humat merupakan suatu senyawa organik yang relatif resisten, berasal dari dekolnposisi bahan organik, larut dalam basa dan mengendap dalam asam. Di alam, senyawa ini dapat ditemukan di dalam bahan organik tanah, kompos, dan batubara dengan jumlah dan karakteristik yang berbeda-beda. Di tanah, asam humat dihasilkan dari penguraian dan modifikasi sisa organisme baik hewan maupun tumbuhan. Asam humat memiliki peranan yang penting dalam memperbaiki kesuburan tanah dan pertumbuhan tanaman. Asam humat dapat merangsang pertumbuhan akar dan bagian atas tanaman. Karena peran pentingnya tersebut, maka dilakukan penelitian tentang penggunaan asam humat hasil ekstraksi dari bahan yang berbeda untuk mengetahui pengaruhnya terhadap pertumbuhan tanaman, dalam hal ini adalah semaian tanaman padi.
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Judul: Pengaruh asam humat dan cara pemberiannya terhadap pertumbuhan dan produktivitas tanaman padi (Oryza sativa)
Abstrak: Agricultural land in Indonesia degraded continuously, characterized by decreasing in soil organic matter resulting from the utilization of chemical fertilizers which is not followed by organic fertilizers. In the rice field, the decrease of organic matter is followed by soil compacting and the decrease in soil pH. In order to increase paddy production, it is needed to improve the soil qualities plants growth. This can be achieved by providing ameliorants such as organic matter with chemical fertilizers. But there is a problem in applying organic matter because of its huge volume. Therefore, it is necessary to find a way to replace the organic matter with other materials that are easier not only in procurement but also in application. Humic acid is an extract of organic material which is expected to be able to replace the role of organic matter in improving physical, chemical, and biological properties of soils. Humic acid is expected to be able for improve plant growth through its role in accelerating the absorption of soil nutrients and water. The research was conducted in a greenhouse located at Cikabayan, Bogor Agricultural University with paddy var. Ciherang as the indicator plant. Soil was taken from Situ Gede, Bogor. Basal fertilizers were 300 kg/Ha SP-18, 200 kg/Ha KCl, and 200 kg/Ha urea. Humic acid dosages used were 0 L/Ha, 5 L/Ha, 10 L/Ha and 15 L/Ha. The methods of humic acid application were spraying on the surface of leaves, spraying underside of leaves, and spraying on the soil. The result showed that humic acid can increase the growth of rice plants by increasing tiller number. Humic acid dosage of 15 L/Ha spraying on the soil is the best treatment indicated by tiller number and dry weight of unhulled rice.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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