Judul: The Effect of Doses of Phosphorus and Potassium Fertilizers on the Growth and Production of Soybean (Glycine max (L.) Merrill)
Abstrak: Kedelai merupakan salah satu komoditas prioritas yang diupayakan untuk ditingkatkan produksinya guna mengurangi impor. Upaya peningkatan produksi nasional kedelai di antaranya perbaikan teknik budi daya melalui pengaturan pupuk. Pupuk fosfor (P) dan kalium (K) menjadi salah satu pupuk dasar yang dibutuhkan untuk budi daya kedelai. Penelitian ini bertujuan mendapatkan informasi mengenai pengaruh dosis pupuk P dan K terhadap pertumbuhan dan produksi kedelai. Penelitian dilakukan di Kebun Percobaan IPB Sawah Baru dari bulan September hingga Desember 2021. Percobaan menggunakan rancangan kelompok lengkap teracak (RKLT) dengan dua faktor percobaan, yakni dosis pupuk P (0, 50, 100, dan 150 kg SP-36 ha-1) dan dosis pupuk K (0, 100, dan 150 kg KCl ha-1). Varietas yang digunakan adalah Anjasmoro. Hasil penelitian menunjukkan pemberian pupuk P mempercepat umur panen serta menaikkan indeks luas daun, nilai kehijauan daun fase R1, bobot kering tajuk, laju pertumbuhan tanaman fase R5−R8, bobot biji per tanaman, bobot ubinan, dan potensi hasil kedelai. Dosis 150 kg SP-36 ha-1 menghasilkan bobot biji per tanaman, bobot ubinan, dan potensi hasil tertinggi dibanding dosis lainnya. Hasil panen perlakuan pupuk P 100 kg SP-36 ha-1 dan 150 kg SP-36 ha-1 melampaui potensi hasil varietas. Pemupukan K memperpanjang fase pengisian polong (R5) dan meningkatkan tinggi tanamana pada 9 MST, bobot kering tajuk, bobot biji per tanaman, bobot 100 butir, bobot ubinan, dan potensi hasil kedelai. Dosis 150 kg KCl ha-1 menghasilkan komponen produksi kedelai tertinggi dibanding dosis lainnya., Soybean is one of the priority commodity which production is being increased in order to reduce imports. Efforts to increase national soybean production by improving cultivation techniques through fertilizer regulation. Phosphorus (P) and potassium (K) fertilizers are one of the basic fertilizers needed for soybean cultivation. This research aims to obtain information on the effect of doses of P and K fertilizers on soybean growth and production. The research was conducted at Sawah Baru Experimental Field and Post-harvest Laboratory of IPB University from September to December 2021. This research used a randomized complete block design (RCBD) with two experimental factors, the dose of P fertilizer (0, 50, 100, and 150 kg SP-36 ha-1) and the dose of K fertilizer (0, 100, and 150 kg KCl ha-1). Variety used was Anjasmoro. The results showed that the application of P fertilizer accelerated harvest age and increased leaf area index, leaf greenness in R1 phase, culm and leaf dry weight, rate of plant growth in R5−R8 phase, weight of seeds per plant, tile weight, and soybean yield potential. A dose of 150 kg SP-36 ha-1 produced the highest weight of seeds per plant, tile weight, and yield potential compared to other doses. The yields of fertilizer treatments of P 100 kg SP-36 ha-1 and 150 kg SP-36 ha-1 exceeded the yield potential of the variety. K fertilization extended age of pods filling (R5) and increased plant height at 9 WAP, culm and leaf dry weight, weight of seeds per plant, weight of 100 seeds, tile weight, and soybean yield potential. The dose of 150 kg KCl ha-1 resulted in the highest soybean production component compared to other doses.
Keyword: age of pods filling, culm and leaf dry weight, harvest age, seed weight, yield potential

Judul: Growth and Productivity of Soybean with Phosphate Fertilization Dose and Frequency on Saturated Soil Culture in Tidal Swamp
Abstrak: Konsumsi kedelai di Indonesia tahun 2020 mencapai 2,87 juta ton, sedangkan produksi nasional hanya 613.300 ton karena luas lahan kedelai menurun akibat persaingan komoditas dan perubahan lahan pertanian. Lahan pasang surut menjadi alternatif peningkatan areal pertanian menggunakan teknik budidaya jenuh air. Penelitian bertujuan mempelajari dosis dan frekuensi pemupukan P terhadap pertumbuhan dan produktivitas kedelai dengan budidaya jenuh air di lahan pasang surut. Penelitian menggunakan rancangan kelompok lengkap teracak faktorial dengan dua faktor dan tiga ulangan. Faktor pertama adalah dosis pupuk P terdiri atas: 36, 72, dan 108 kg P2O5 ha-1 (180, 360, dan 540 kg Fertiphos ha-1). Faktor kedua adalah frekuensi pemupukan P terdiri atas; pada saat tanam 0 hari setelah tanam (HST), 0 dan 30 HST, dan 0, 30, 60 HST. Perlakuan berbagai dosis pemupukan fosfat berpengaruh nyata terhadap peningkatan tinggi tanaman, jumlah cabang, jumlah daun, luas daun, bobot basah batang, bobot kering batang, bobot kering daun, jumlah polong isi, jumlah polong hampa, bobot biji ubinan, dan produktivitas. Perlakuan berbagai frekuensi pemupukan fosfat berpengaruh nyata terhadap peningkatan tinggi tanaman, jumlah cabang, jumlah bintil akar, jumlah polong isi, dan jumlah polong hampa. Dosis pupuk 108 kg P2O5 dan frekuensi pemupukan fosfat dengan tiga kali pemupkan pada 0, 30, dan 60 HST menjadi kombinasi terbaik untuk peningkatan produksi kedelai. Dosis pupuk 108 kg P2O5 ha-1 menghasilkan produksi kedelai tertinggi sebesar 2,60 ton ha-1., Indonesia's soybean consumption is estimated to reach 2.87 million tons in 2020. Meanwhile, the national production is only 613,300 tons as the soybean area is decreasing due to commodity competition and agricultural land changes. Tidal land is an alternative to increase agricultural area using water-saturated cultivation techniques. The research aimed to study the dose and frequency of P fertilization on the growth and productivity of soybean plants with water-saturated cultivation on tidal land. The study used a factorial randomized complete block design with two factors and three replications. The first factor was the dose of P fertilizer consisting of: 36, 72, and 108 kg P2O5 ha-1 (180, 360, and 540 kg Fertiphos ha-1). The second factor is the frequency of P fertilization consisting of; at planting 0 days after planting (DAP), 0 and 30 DAP, and 0, 30, and 60 DAP. The treatment of various doses of phosphate fertilization had a significant effect on increasing plant height, branch number, leaf number, leaf area, stem fresh weight, stem dry weight, leaf dry weight, number of filled pod number, number of empty pods, seed weight, and productivity. The treatment of various phosphate fertilization frequencies significantly increased plant height, number of branches, number of root nodules, number of filled pods, and number of empty pods. The fertilizer dose of 108 kg P2O5 ha-1 and phosphate fertilization frequency at 0, 30, and 60 DAP the best combination for increasing soybean production. The fertilizer dose of 108 kg P2O5 ha-1 resulted in the highest soybean seed yield as much as 2.60 tons ha-1.
Keyword: Fosfor, Lahan rawa, Varietas Demas 1, Phosphorus, swamplands

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