Judul: Perencanaan penggunaan lahan dan pengembangan usahatani berbasis kopi untuk sistem pertanian berkelanjutan di DAS Ketahun Hulu Provinsi Bengkulu
Abstrak: Ketahun Hulu watershed is part of Ketahun watershed, administratively it is mainly located in Lebong district and a small portion of it is located in North Bengkulu and Rejang Lebong districts of Bengkulu province. This study was aimed to identify landuse and agrotechnology characteristics in Ketahun Hulu watershed, and to arrange land use planning and coffee based farming development for sustainable agricultural systems in the Ketahun Hulu watershed. To achieve a sustainable agriculture, there are 3 (three) indicators that should be fulfilled : a) total farmer’s income should be high enough support a life worth living, b) erosion should be less than tolerable soil loss (ETol), c) agrotechnologies should be acceptable and replicable to the farmers. This study was focus on intensive observation sites covering 14,844 hectares located in one of sub watershed that represent characteristics of the watershed. Land capability was evaluated using Klingebiel and Montgomery method, erosion was predicted using USLE equation developed by Wishmeier and Smith (1978), and farming income was analyzed using cash flow analysis method. Results of this research showed that predicted erosion in the existing cropping pattern and agrotechnologies in Ketahun Hulu watershed generally greater than ETol; it ranged from 2,47 – 683,18 tons/hectare/year while ETol was ranged from 13,45 – 36,38 tons/hectare/year. Total incomes of farmers were much lower than a decent income (Rp. 18.000.000,-/householder/year). Alternative agrotechnologies to meet the indicators of sustainable agricultural systems were recommended with two alternatives. To increase farmer’s income to meet the income of decent living, the source of income such as livestock was introduced in to the existing farming systems. Simulation of agrotechnologies show that alternatives of agrotechnology can reduce erosion to lower than ETol and to increase farmer’s income up to a decent income. Alternative agrotechnolgy 1 which consisted of grass strip plus litter mulch, fertilizer and livestock including 30 chickens and 5 goats can reduce erosion to lower than ETol (2,45 – 22,77 tons/hectares/year) and increase farmer’s income up to a decent living (Rp. 18.855.000,- to Rp. 24.915.000,-/householder/year). Alternative agrotechnology 2 which consisted ridge terrace plus litter mulch, fertilizer and livestock including 30 chickens and 5 goats can reduce erosion to lower than ETol (2,47 – 22,77 tons/hectares/year) and increase farmer’s income up to a decent living (Rp. 18.635.000,- to Rp. 24.695.000,-/householder/year). Spatial planning of recommended agrotechnologies was extrapolated into the watershed in Ketahun Hulu Watershed.
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Judul: Perencanaan Penggunaan Laban untuk Pembangunan Pertanian Berkelanjutan di DAS Lahumbuti Sulawesi Tenggara
Abstrak: Land use which is not compatible with land capability and lack of awareness to apply soil conservation measures, are the causes of increasing erosion and decreasing soil productivity which ultimately lead to low income of the farmers. Therefore, there is a necessity for proper land use management plan, particularly in the Lahumbuti catchment for achieving sustainable agricultural development. The research that has been conducted in Lahumbuti catchment. has the objectives of evaluating land use and land capability, and also le::rrning the agrotechnolo-g-; applied in the Lahumbuti catchment. Beside that, the study was also aimed at designing alternative for land use management plan which is compatible with land capability to achieve sustainable watershed management at Lahumbuti catchment. Method used in this research was survey method that comprised collection of primary data and secondary data. Primary data includes (a) physical condition of the land (steep slope and length of slope, permeability, effective soil depth, drainage, texture, stucture and content of the soil organic matter) and (b) socio-economic condition (demography, production facility, cost, farmers income and agrotechnology applied in the study site), evaluation of suitability betwen land use and land capability using Klingebiel and Montgomery criteria, erosion estimate using USLE method, calculation of Etol using Hammer method (1981 and evaluation of living standard appropriateness using Sajogyo and P. Sajogyo ( 1990 ). Secondary data are in the form of daily rainfall data, facts in the district, topographic map and soil map. Research result showed that generally land use in Lahumbuti catchment are accordance with their land capability, although there were several farming activities that were conducted on steep slope. Planting pattern and agrotechnology adopted by farmer were still traditional. Result of erosion prediction at intensive obsevation site indicates that the occuring erosion (13,03-262,10 tonnes/ha/year) were greater than the soil loss tolerable (8,65-48,% tonnes/ha/year), resulting in decline of land productivity and farmers low income (Rp. 2.822.650,- - Rp. 8.033.100,- HH/ha/year). Therefore, there is need for change in cropping pattern and agrotechnology, accompanied with soil conservation measures so that erosion could be reduced to a minimum level which is smaller than the tolerable level. Pursuant to equality of land capability class and types of cultivated crop betwen the intensive observation sites and the land units at the whole of Lahumbuti catchment, land use recomendation in the catchment is that at land class I (21.870 ha) and land class II (1213,5 ha) the suitable land used are mixed garden and dry land, there would be inter cropping (tumpangsari, tampang si1>ip) and multiple cropping, accompanied by mulch and construction of bund terrace. Forest and shrubland could be converted to mixed garden and dry land or agroforestry system. Land class III (11.624,1 ha) and class IV(28.373,7 ha) are
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Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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