Judul: Optimization of Fertilizer Doses for Yard Long Bean  Cultivation Using Fertigation Through Drip Irrigation
Abstrak: Pemupukan harus diberikan dengan dosis yang tepat sesuai kebutuhan tanaman dan keadaan lahan yang digunakan. Pemupukan dosis yang optimum dengan penggunaan irigasi tetes diterapkan untuk meningkatkan efisiensi produksi kacang panjang. Penelitian ini bertujuan mendapatkan dosis rekomendasi pemupukan optimum bagi budidaya kacang panjang varietas Parade Tavi berdasarkan hasil analisis tanah. Penelitian dilakukan pada tanah latosol dengan kandungan hara P-tersedia 29 ppm (sedang), K-tersedia 39 ppm (sedang), 2,2% C- Organik (sedang), serta pH 5,82 (agak masam) di Kebun Percobaan Cikarawang, Institut Pertanian Bogor pada bulan Juli hingga Oktober 2022. Penelitian menggunakan rancangan kelompok lengkap teracak dengan 5 dosis pemupukan, yaitu 0%, 50%, 100%, 150%, 200% dari rekomendasi pemupukan Ferads (164,25 kg N ha-1 ; 56,16 kg P2O5 ha-1 ; dan 56,4 kg K2O ha-1 ) dan dilakukan pengulangan sebanyak 5 kali. Hasil penelitian menunjukkan tidak adanya pengaruh nyata variasi dosis pemupukan terhadap setiap parameter pengamatan. Lahan direkomendasikan untuk tidak dipupuk sama sekali dengan capaian bobot panen hingga 17,4 ton ha-1 pada periode panen 33 hari., Fertilizers must be given at the right doses according to the needs of the plants and the conditions of the land used. Optimum fertilization doses with the use of drip irrigation can be applied to increase the efficiency of yard long bean production. This study aims to obtain the optimum fertilizer recommendation doses for yard long bean var. Parade Tavi cultivation based on the results of soil analysis. This research was conducted on latosol soil with available content of available P 29 ppm (moderate), available K 39 ppm (moderate), 2.2% C-Organic (moderate), and pH 5.82 (slightly acidic) at Cikarawang Field Station, IPB University from July to October 2022. The research used a randomized complete block design with 5 doses of fertilization, 0%, 50%, 100%, 150%, 200% of Ferads fertilization recommendation (164,25 kg N ha-1 ; 56,16 kg P2O5 ha-1 ; and 56,4 kg K2O ha-1 ) and replicated 5 times. The results showed no significant effect of variations in fertilizer doses on each observation parameter. The Field was recommended not to be fertilized at all with a yield up to 17.4 ton ha-1 at 33 harvest days.
Keyword: dosis pemupukan, Ferads, irigasi tetes, Parade Tavi

Judul: Optimization of Spinach Fertilization Based on Soil Analysis Using Fertigation Through Drip Irrigation Systems
Abstrak: Pemupukan melalui irigasi tetes berdasarkan analisis tanah diharapkan dapat meningkatkan produktivitas bayam varietas Maestro. Penelitian dilaksanakan di Kebun Percobaan Cikarawang, Institut Pertanian Bogor dengan jenis tanah latosol, kandungan P-tersedia 3,9 ppm (sangat rendah), K-tersedia 40,2 ppm (sedang), C Organik 1,92%, dan pH 5,83. Penelitian ini bertujuan mendapatkan dosis rekomendasi pemupukan yang tepat untuk bayam berdasarkan hasil analisis tanah melalui sistem irigasi tetes dan menguji pengaruh potensi pupuk untuk dua kali tanam tanpa preplant dan fertigasi. Penelitian terdiri dari dua kali penanaman menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) faktor Tunggal dengan 5 ulangan dan 5 taraf pemupukan yaitu 0% X, 50% X, 100% X, 150% X, dan 200% X (X adalah rekomendasi berdasarkan program Ferads). Data dianalisis menggunakan uji-F dengan α 5% dan uji lanjut menggunakan analisis regresi. Hasil penelitian menunjukkan pada penanaman pertama didapatkan dosis optimum untuk bobot per bedeng marketable, bobot per bedeng total, perkiraan bobot panen per hektar marketable, dan perkiraan bobot panen per hektar total berturut-turut yaitu sebesar 151%, 133%, 135%, dan 132% dari dosis rekomendasi Ferads (219 kg N ha-1 , 274 kg P2O5 ha-1 , dan 149 kg K2O ha-1 ). Dosis 100% rekomendasi Ferads digunakan karena kenaikan hasil tidak signifikan meskipun diberikan dosis pupuk yang lebih tinggi. Dosis optimum tidak diperoleh pada penanaman kedua karena hasil analisis regresi tidak menunjukkan respon kuadratik. Residu pemupukan tidak mempengaruhi produksi bayam varietas Maestro secara keseluruhan sehingga analisis tanah perlu dilakukan di setiap musim tanam bayam., Fertilization through drip irrigation based on soil analysis is expected to increase the productivity of Maestro spinach varieties. The research was carried out at the Cikarawang Experimental Garden, Bogor Agricultural Institute with latosol soil type, P-available content of 3.9 ppm (very low), K-available 40.2 ppm (medium), C-Organic 1.92%, and pH 5 .83. This research aims to obtain the correct recommended dose of fertilizer for spinach based on the results of soil analysis using a drip irrigation system and testing the potential effect of fertilizer for two plantings without preplant and fertigation. The research consisted of two plantings using a single factor Randomized Complete Group Design (RKLT) with 5 replications and 5 levels of fertilization, namely 0% X, 50% X, 100% X, 150% X, and 200% X (X was a recommendation based on the Ferads program). Data were analyzed using F-test with α 5% and further testing using regression analysis. The results of the research showed that in the first planting, the optimum dose was obtained for weight per marketable bed, total weight per bed, estimated marketable harvest weight per hectare, and estimated total harvest weight per hectare respectively, namely 151%, 133%, 135%, and 132%. % of Ferads recommended dose (219 kg N ha-1 , 274 kg P2O5 ha-1 , and 149 kg K2O ha-1 ). The 100% dose recommended by Ferads was used because the increase in yield was not significant even though a higher fertilizer dose was given. The optimum dose was not obtained in the second planting because the results of the regression analysis did not show a quadratic response. Fertilizer residue does not affect the overall production of the Maestro spinach
Keyword: Ferads, fertigation, fertilizer dose, production, 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