Judul: Pengaruh soil conditioner berbasis bahan alami terhadap sifat fisik dan biologi tanah podsolik merah kuning
Abstrak: One type of the most important soil in dry land is Red Yellow Podzolic. These soils have many problems. The main problems in this soil are poor physical and biological properties, it has high bulk density, low permeability, low water holding capacity and low microbial activities. However, this land has a potential, because it covers about 25%-27% of the total mainland of Indonesia. Therefore, soil and water conservation efforts are needed to prevent and repair the poor soil properties. One of soil and water conservation efforts needed is the use of chemical either in the form of synthetic compounds or organic materials that can increase soil aggregate stability and prevent erosion is highly needed. This research was aimed to develop and identify the effect of organic Soil Conditioner based on rice straw organic matter and city organic waste on physical and biological properties of Red Yellow Podzolic Soil. Soil Conditioner used was the compost in the form of briquettes. The experiment was arranged in randomized design with two factors, treatments of soil conditioner include city organic waste, rice straw, and control, with three level of doses, A 1:20, B 1:30 and C 1:40. Each treatment was repeated 3 times to make 27 experimentals units. The results of this research showed that the Soil Conditioner based on city organic waste and rice straw were significantly decreased the bulk density and significantly increased porosity, permeabilty, saturated water content, the water holding capacity, very rapid drainage pores as well as total microbial and total fungi activities of Red Yellow Podzolic Soil.
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Judul: Pemanfaatan kompos jerami padi dan sampah pasar sebagai soil conditioner
Abstrak: Generally, dry land of agriculture is characterized by low soil fertility and availability of water for irrigation depend on rainfall. Therefore, development dry land agriculture is required conservation efforts intended to improve soil structure, reduce erosion, minimize loss of nutrients and increase water availability. Improvement of physical, chemical and biological soil properties can be done by using soil conditioner. This research aimed to formulate soil conditioner from rice straw raw material, waste vegetables market, cow dung and biochar. The research was conducted on April to September 2010 in plastic house was build in the field of university farm of Bogor Agriculture University in Cikabayan Darmaga, Bogor. Physical and chemical analysis were conducted in the laboratory of Department of Soil Science and Land Resources, Faculty of Agriculture, IPB, whereas biological analysis was conducted in the Plantation Research Institute. The research was initiated with the composting of rice straw and waste vegetables market materials. The resulting compost was used as the base material to formulate soil conditioner which were enriched by biochar, extraction of goat urine and manure and CuSO4. The results showed that the largest compost material depreciation occurred in compost D and B of 69,29% and 54,7%, respectively. Average of saturated water content of all compost were over than 200%, while bulk density were 0,36 g/cm3 (compost D), 0,29 g/cm3 (compost C), 0,22 g/cm3 (compost A) and 0,15 g/cm3 (compost B). Macro nutrients content (N, P, K and Mg) in compost C and D were lower than compost A and B, on the contrary Ca content of compost C and compost D were higher than compost A and B namely were 1,16% and 3,16%, respectively. Total population of microorganisms was different for each type of compost. The highest fungal population was found in compost A (5.05 x 105) and the highest bacterial population in compost C (4.45 x 1011). Compost which were formed from materials A and B were the best compost due to has a lower bulk density and higher of nutrient content (N, P, K, Mg, Fe, Cu, Mn, Zn and total fungal) comparing with C and D materials. The bulk density of briquettes soil conditioner after compaction treatment was 0,64 gr/cm3. Soil conditioner B has a higher of macro and micro nutrients contents than soil conditioner A, C and D. Soil conditioner A has a higher colonies of fungal (9.3 x 106) and soil conditioner D has a lot of colonies of bacteria (5,05 x 1011). Based on the nutrients content, soil conditioner with formulation B is the best formulation as compared with formulations A, C and D.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf