Judul: Penilaian Opsi Budi Daya Padi Sawah Tadah Hujan Adaptif Kekeringan: Studi Kasus Kabupaten Subang
Abstrak: Extreme climate events, particularly drought significantly affectproduction of rainfed lowland rice in Indonesia. This might affect food security. This study aims to assess alternative technologies or crop management strategies of rainfed lowland rice more adaptive to drought in Subang, West Java. Technology options and strategies are determined through surveis and crop simulation models of DSSAT (Decision Support System for Agrotechnology Transfer). Input data for the model consists of a 21-year daily climate data (1991-2011), soil physic and chemical properties, genetic data of IR 64 rice varieties and rice cultivation technologies. The cultivation technology options being tested included soil management (fertilization) and crop management (varieties and planting time). Simulations was carried out according to the time of planting from January to December with 15 days interval. The results of field survei confirmed that the main problem in rainfed rice at Subang District was drought. The simulation results showed that the main options to address drought was to set appropriate planting time with the use of proper cultivation technology (balanced fertilizers). In general, the appropriate time for rainfed lowland rice planting was rainy season (October-April) the yield can reach 6.0 ton/ha, while dry season (May-September can be lower than 1.0 ton/ha. The use of SST Nino 34 index to see the phenomenon of ENSO which affecting rice yield variance of rain. So that farmers can appropriate started of planting time based on seasonal climate forecast to solve the drought problem. The recommended amount of fertilizer for the rainfed lowland rice at Subang was 300 kg/ha of inorganic fertilizer and 5 tons/ha of organic fertilizer with planting space of 40 × 40 cm. The use of this technology resulted in yield of more than 5 ton/ha with B/C ratio of about 1.76.
Keyword: simulation., rainfed rice system, rice farming system, DSSAT

Judul: Evaluasi Teknologi Budidaya Padi Adaptif Terhadap Perubahan Iklim
Abstrak: Perubahan iklim memberikan dampak secara langsung pada sektor pertanian. Tujuan penelitian ini untuk mengevaluasi dampak perubahan iklim terhadap pertanaman padi dan mendapatkan kombinasi teknologi budidaya padi yang adaptif terhadap perubahan iklim. Analisis dilakukan dengan menggunakan model DSSAT (Decision Support System fot Agrotechnology Transfer). Teknologi budidaya yang dievaluasi terdiri dari 10 opsi yang disusun berdasarkan hasil survey teknologi budidaya yang digunakan petani dan yang direkomendasikan oleh lembaga penelitian. Evaluasi dampak perubahan iklim dilakukan dengan mengunakan data proyeksi iklim tiga tahun dari skenario RCP 4.5 dan RCP 8.5 yang masing-masing merepresentasikan kondisi iklim normal, ekstrem kering, dan ekstrem basah. Hasil analisis menunjukkan bahwa Perubahan Iklim berpengaruh nyata terhadap hasil tanaman padi dan waktu tanam optimal. Secara umum, pada wilayah penelitian perubahan iklim diperkirakan akan memberikan dampak positif baik pada padi sawah tadah hujan maupun beririgasi untuk hampir semua opsi teknologi apabila waktu tanamnya tepat.
Keyword: DSSAT, perubahan iklim, produktivitas, RCP 4.5

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology