Judul: ustainable Land Use Planning in the Akelamo Watershed, West Halmahera
Abstrak: DAS Akelamo Kabupaten Halmahera merupakan salah satu DAS kritis yang diprioritaskan penanganannya untuk rehabilitasi hutan dan lahan sebagai akibat perluasan areal pertanian dan terbatasnya pengelolaan lahan secara konservasi yang mempengaruhi kerusakan lahan dan hutan, meluasnya lahan kritis serta meningkatkan laju erosi tanah. Selain permasalahan lahan kritis dan erosi tanah, pedesaan diwilayah DAS Akelamo termasuk dalam Inpres Desa Tertinggal (IDT) dimana sumber ekonomi petani tergantung pada pemanfaatan lahan dan hutan. Pengelolaan lahan DAS Akelamo secara berkelanjutan diperlukan perencanaan penggunaan lahan melalui pengembangan berbagai alternatif penggunaan lahan. Penelitian ini merupakan langkah awal dalam mencari solusi pengelolaan DAS secara berkelanjutan dengan tujuan mengevaluasi kemampuan dan kesesuaian lahan, keberlanjutan penggunaan lahan aktual dan menentukan alternatif penggunaan lahan berkelanjutan berdasarkan aspek ekologi erosi tanah di bawah ETol dan sosial-ekonomi pendapatan usaha tani dan produksi beras memenuhi kebutuhan masyarakat. Penelitian ini menggunakan metode survei tanah dengan teknik penarikan sampel strata bertujuan (stratified purposive sampling) dan pengumpulan data usaha tani menggunakan tehnik wawancara. Analisis data mencakup evaluasi kemampuan dan kesesuaian lahan, erosi tanah, pendapatan usaha tani, produksi beras, standar erosi yang ditoleransi, kebutuhan hidup layak dan konsumsi beras yang di sesuaikan dengan perkembangan jumlah penduduk. Standar evaluasi penggunaan lahan berkelanjutan meliputi : 1) jangka pendek 10 tahun ke depan yaitu rata-rata erosi kurang dari ETol (24 ton ha-1 thn-1), pendapatan usaha tani mencapai Rp 200.249 juta thn-1 dan produksi beras mencapai 5.928 ton dan 2) jangka panjang 25 tahun ke depan yaitu rata-rata erosi kurang dari ETol, pendapatan usaha tani mencapai Rp 290.021 juta thn-1 dan produksi beras mencapai konsumsi 8.586 ton Hasil penelitian menunjukan potensi lahan di DAS Akelamo berdasarkan kemampuan lahan meliputi kelas II, III dan IV seluas 30.988 ha (47%) dan kelas V, VI, VII dan VIII seluas 35.583 ha (53%). Kesesuaian lahan di wilayah perencanaan untuk pengembangan pertanian dominan kelas sesuai (S2 dan S3) dengan komposisi tanaman pangan seluas 16.783 ha (62%), hortikultura seluas 20.670 ha (76%) dan perkebunan seluas 18.924 ha (70%). Penggunaan lahan aktual belum dilaksanakan secara berkelanjutan dari aspek ekologi menunjukan laju erosi lebih dari erosi yang ditoleransi dimana rata-rata erosi tanah khusus lahan pertanian sebesar 40 ton ha-1 thn-1 dan aspek sosial-ekonomi meliputi pendapatan usaha tani sebesar Rp 186.689 juta thn-1 dan produksi beras sebesar 799 ton belum dapat memenuhi kebutuhan masyarakat dalam jangka panjang., Study of sustainable land use planning in the Akelamo watershed aims to evaluate the capability and suitability land, sustainability the actual land use and to determine alternative sustainable land uses based on the ecological aspects of soil erosion under the tolerable erosion and socio-economic farm income and rice production to meet standard quality of little. Environmental data was observed during the soil survey with stratified purposive sampling and farming data by the interview. Sustainable land use analysis was determined tolerable soil erosion, decent living income and rice sufficiency. The potential land in the Akelamo watershed based on land capability include class II, III and IV covering an area of 30.988 hectares (47%), while the not potential one consist of class V, VI, VII and VIII cover 35.583 hectares (53%). Suitable land for agricultural development in accordance
Keyword: Land use planning, Sustainable land use, Soil erosion, Farming incomes, Rice production

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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