Judul: Sumber dan Frekuensi Aplikasi Larutan Hara sebagai Pengganti AB Mix pada Budidaya Sayuran Daun secara Hidroponik
Abstrak: The objective of this research to determinate the frequency and source of nutrient applications on growth and yield of kangkong (Ipomoea sp.), caisin (Brassica juncea), and kale (Brassica oleraceae Var Acephala) in hydroponics. The experiment were arranged in a RCBD (Randomized Completely Block Design) with two factors, first factor source of nutrient (AB Mix, NPK 15:15:15, and NPK 12:14:12), and second factor is method of application (one time and two time) with four replication so there are 24 experimental units. The result show NPK 15:15:15 have similar effect with AB Mix in kangkong, caisin, and kale.With one time frequency application, the best fertilizer source is NPK 15:15:15, while with two time application the best fertilizer is AB Mix.
Keyword: nutrient solution., NPK 12:14:12, NPK 15:15:15

Judul: Growth of Water Spinach and Spinach Due to the Application of Inorganic Liquid Fertilizer in the Hydroponic System
Abstrak: Hidroponik adalah salah satu metode alternatif dalam budidaya sayur, metode ini tidak memerlukan area yang luas. Produksi dari hidroponik dapat ditingkatkan dengan pemenuhan nutrisi yang tepat. Penelitian ini bertujuan menganalisis efek penambahan pupuk anorganik cair pada larutan hara AB mix terhadap pertumbuhan tanaman kangkung dan bayam. Rancangan penelitian yang digunakan adalah Rancangan Acak Kelompok. Perlakuan yang diamati adalah konsentrasi larutan hara yang terdiri dari 3 taraf. Perbandingan air, larutan A, larutan B, dan pupuk cair (v/v) yaitu P0 (kontrol) = 1000:5:5:0, P1 =1000:5:5:5, dan P2 = 1000:5:5:15. Parameter yang diamati adalah tinggi tanaman, jumlah daun, jumlah cabang, luas daun, berat segar, berat kering, dilakukan juga uji kualitatif kandungan nitrat daun. Hasil penelitian menunjukkan bahwa perlakuan P0 memiliki pertumbuhan tercepat, sedangkan pertumbuhan paling lambat terlihat pada P2. Uji nitrat daun P2 menunjukkan hasil yang negatif. Perlakuan P0 juga memiliki berat segar dan berat kering tanaman yang paling tinggi dibanding dua perlakuan lainnya. Penambahan pupuk anorganik cair tidak dapat meningkatkan pertumbuhan pada kangkung dan bayam., Hydroponics is an alternative method in vegetable cultivation, this method does not require a large area. Hydroponics production can be increased with the fulfilment of proper nutrition. This research aimed to analyze the effect of adding liquid inorganic fertilizer to the AB mix nutrient solution on water spinach and spinach growth. This research used a Randomized Block Design. The treatments observed were the concentration of nutrient solution which consisted of 3 levels. The treatments were mixed of water, solution A, solution B, and liquid fertilizer (v/v), namely P0 (control) = 1000:5:5:0, P1 =1000:5:5:5, and P2 = 1000:5:5:15. The parameters observed were plant's height, number of leaves, number of branches, leaves area, leaves nitrate content, and plant fresh and dry weights. The results showed that the P0 treatment had the fastest growth, while the slowest growth was seen in P2. The leaf nitrate test of P2 plants showed negative results. The P0 treatment also had the highest fresh and dry weights per plant compared to the other two treatments. The addition of liquid inorganic fertilizer did not increase the growth of water spinach and spinach.
Keyword: AB mix, hydroponics, liquid inorganic fertilizer, spinach, water spinach

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