Judul: Potensial Redoks (Eh) dan Kelarutan Fe dan Mn serta Kaitannya dengan Pertumbuhan dan Produksi Padi pada Budidaya Padi Sistem Konvensional dan System of Rice Intensification (S.R.I.)
Abstrak: Peningkatan jumlah penduduk berdampak dengan meningkatnya permintaan akan bahan pangan seperti beras. Namun meningkatnya permintaan beras tidak diimbangi dengan produksi beras yang dihasilkan. Pemerintah melalui Departemen Pertanian telah melakukan berbagai usaha untuk meningkatkan produksi beras dalam negeri. Salah satu usaha yang memiliki potensi untuk meningkatkan produksi beras adalah System of Rice Intensification (S.R.I.). S.R.I. dikembangkan sejak tahun 1980an di Madagaskar oleh Fr. Henri de Laulanie. Konsep dasar S.R.I. adalah penanaman bibit muda umur 7-15 hari, jarak tanaman yang lebar dengan 1 bibit per lubang tanaman dengan posisi akar horizontal, dan pengairan tidak tergenang tetapi cukup jenuh. Proses penggenangan pada budidaya padi konvensional mempengaruhi nilai Eh tanah, dimana pada umumnya jika penggenangan tanah dilakukan secara terus menerus akan mengakibatkan rendahnya niai Eh yang akan mengakibatkan terlarutnya unsur mikro seperti Fe dan Mn Penelitian ini bertujuan mempelajari pengaruh sistem budidaya padi terhadap sifat kimia tanah seperti pH, Eh, kandungan Fe dan Mn dalam tanah, pertumbuhan dan produksi padi. Penelitian ini menggunaan Rancangan Acak Kelompok (RAK) dengan empat perlakuan yaitu konvensional, S.R.I. anorganik, S.R.I. organik, dan S.R.I. semiorganik. Nilai pH dan Eh diukur dengan menggunakan pH dan Eh meter, sedangkan Fe dan Mn didapat dengan cara mengekstrak tanah dengan HCl 0.1 N lalu diukur dengan AAS
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Judul: Pengaruh Perbedaan Karakteristik Kimia dan  Mineral serta Penambahan Bahan Organik terhadap Pertumbuhan dan Produksi  Padi yang Ditanam dengan Metode SRI
Abstrak: The necessity of food especially rice increase with increasing in human population. One of a very popular system in the cultivating of paddy is the System of Rice Intensification (SRI). Although SRI is believed can increase the paddy production without inorganic fertilizer and optimizing water use, but there are several problems which has not been fully understand yet in order to apply SRI, especially about the land condition. This research was aimed to study mineralogical and chemical soil characteristics and organic matter application in order to support the growth and the production of paddy cultivating by comparing SRI and conventional method. Soil samples were collected from four locations i.e: Cihideung, Bogor (Chd, Bgr), Sindangbarang, Bogor (Sbr, Bgr), Margakaya, Karawang (Mgk, Krw) and Bobojong, Cianjur (Bbj, Cjr), two water management levels, i.e: convensional (K) and SRI with irrigation during five days (S). Each water management levels were combined with two treatments of organic matter applications, i.e: plus compost application (B1) and without compost application (BO). Treatments were desained in Factorial Completely Random Design with 16 treatments and three times replications. Totally there were 48 experimental units. Chemical properties (C-organic, total N, and K) of Bobojong soil showed better result than the other soils, and the texture of Cianjur soil was silty clay. Quartz was the most dominant mineral in sand fraction for all soils, and kaolinite was the most abundant mineral in clay fraction. It was also found easily weathered mineral which show that natural fertility in the research location were high, especially on Sindangbarang and Cianjur soils. Compost application 7 ton/ha was not significantly different in increasing the production and the growth of paddy. Water irrigation using SRI method during five days also can not increase the production and the growth of paddy, except if both treatments were combined. Meanwhile, based on the production and the growth parameters, Sindangbarang (Bogor) soil showed better response for SRI application than other soil. SRI application in different soils gave variety results for paddy production.
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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