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: Studi Perencanaan Pengelolaan DAS dengan Model Optimasi Penggunaan Lahan di Bagian Hulu DAS Mahakam
Abstrak: Land use which is not in accordance with the land capability, will cause land degradation. In Indonesia, there is progressive increase of critical land area size, every year, and this exerts an impact toward watershed damage. Objectives which are sought in the planning of watershed management often negate each other because from one point of view, there is a desire to maintain natural resources sustainability, and from other (economic) point of view, there is a desire to increase farmer's income. In order to obtain a model for planning sustainable watershed management, land use optiminazation was conducted and designed using the analysis of Linear Goals Programming (L GP) The study area had the size of 29 686 ha, comprising 3 subdistricts (namely Damai, Barong Tongkok and Melak) that were situated in the district of Kutai Barat, the province of East Kalimantan. The formulation of model for land use optimization was designed to achieve four targets, namely peak discharge. reduced rate of erosion (so that it is equal with or smaller than the targeted discharge and tolerable soil loss), ability of each farmer family to fulfill the need for food and rice, and ability of on farm income to create appropriate level of welfare. Research unit was homogeneous land unit. Data source for model input came from improvement of cropping pattern and alternative agrotechnology which was conducted by using simulation of CP factor. Data processing and analysis used the method of SCS, USLE and farm analysis. On the other hand, the completion of model used software General Algebraic Modeling System (GAMS) and Arcview 3,2. Land use with existing cropping pattern gave peak discharge of 116.39 m3/seconcj, erosion between 157-876 tonlha, production of upland rice 1.52 ton GKPlhalyear, and income Rp 3 268 636,-halyear. On the other hand, optimum land use pattern from the six scenarios model, showed better results as compared with the existing condition because ecologically, the land use could maintain the stability of peak discharge, and reduce erosion to the level below the targeted value. Although scenario model la and llla (with land use composition in the form of non irrigated rice field and dry land crop field) gave better result than those of existing conditions, but the occurring erosion were still higher than those in scenario model I, 11, Ill, and IV (with land use composition in the form of non irrigated rice field, dry land crop field, and estate field). This was because the priority for achieving erosion target in scenario la and llla was only up to the tolerable rate of soil erosion. Testing of scenario model I, 11, Ill, and IV showed that there was a tendency for increasing proportion of dry land crop field area size, but on the other hand, decreasing proportion of non irrigated rice field and estate field area size, if the target of achieving living standard is continuously increased. Spatially, recommendation that could be given for /and units of non irrigated rice field, dry land crop field and estate field is in the form of cropping pattern and agrotechnology LI *, L3b* ,
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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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