Judul: Pengaruh Pupuk Anorganik Dan Pupuk Organik Terhadap Produksi Dan Kualitas Ubi Jalar (Ipomoea batatas (L.) Lam) Dan Sifat Kimia Podsolik Jasinga
Abstrak: Podsolic is the soil that has a very wide spread in Indonesia, which reached 47,526 million ha of total land area of Indonesia. Podsolic is soil with organic matter content less than 2 %, base saturation is generally low (<35 %), acid (pH 3.5-5.5), low to high cation exchange capacity depending on the texture and clay mineral, low content of nutrients, especially N, P, K, and Ca, and generally have relatively low fertility rate. Sweet potato is a plant that has little risk of crop failure and has a wide adaptability to the environment, so that it can be cultivated on various types of land, altitude, and different levels of soil fertility. This research is a field experiment of planting sweet potatoes in demonstration plot of BPN RI, Setu village, Jasinga, Bogor District with total area of 1800 m2. The design of treatment randomized complete block design factorial two factors. The first factor is the dose of inorganic fertilizer (15-15-15 and Rock Phosphate), while the second factor is the organic fertilizer (with and without humic). Soil analysis was performed at the Center for Soil Research, Bogor and analysis of the quality of sweet potato conducted at the Laboratory of Technopark, Bogor Agricultural University. This study aims to determine the effect of inorganic fertilizer (15-15-15 and Rock Phosphate), and organic fertilizer (humic) on growth, production and quality of sweet potato (Ipomoea batatas (L.) Lam.) and soil chemical properties Podsolic Jasinga. The results showed that the inorganic fertilizer15-15-15 (Phonska) increased stem length and starch content, while inorganic fertilizer Rock Phosphate tends to produce biomass weight than inorganic compound fertilizer 15-15-15. Interaction between inorganic fertilizer and organic fertilizer significantly increased the number of leaves and weight of tuber. In the treatment without humic, inorganic compound fertilizer 15-15-15 tended to increase Pavailable, whereas giving Rock Phosphate increased pH, P-available, and K-dd. The treatment with humic, giving P1 15-15-15 compound fertilizer and Rock Phosphate dose of R2 increased available-P and soil cation exchange capacity, while lower dose of P2 and R1 increased available-P and soil cation exchange capacity. Organic fertilizer and inorganic fertilizer did not decrease the Al-dd but tended to increase the Al-dd.
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Judul: Effect of Potassium Fertilizer Dosage on Growth, Productivity, and Quality of Sweet Potato Tubers (Ipomoea batatas L.) Clon Tariko Bandung
Abstrak: Ubi jalar (Ipomoea batatas L.) merupakan salah satu komoditas tanaman pangan sumber karbohidrat yang berkembang di Indonesia. Ubi jalar merupakan sumber karbohidrat non-biji dengan konsumsi tertinggi keempat setelah padi, jagung, dan singkong. Selain sebagai tanaman sumber karbohidrat Ubi jalar mengandung berbagai nutrisi yang dibutuhkan tubuh manusia.diantaranya, ß karoten, vitamin C, niacin, riboflavin, thiamin, dan mineral. Pemupukan merupakan perlakuan penambahan unsur hara pada tanah yang dapat meningkatkan pertumbuhan dan produktivitas tanaman budidaya. Pemupukan pada ubi jalar dilakukan untuk meningkatkan ketersediaan hara pada tanah yang dibutuhkan tanaman. Penelitian ini bertujuan untuk menentukan dosis pemupukan ubi jalar yang menghasilkan pertumbuhan dan produksi maksimum untuk ubi jalar klon Tariko Bandung. Percobaan dilakukan di Kebun Percobaan Sawah Baru serta Laboratorium Pasca Panen dan Mikroteknik Departemen Agronomi dan Hortikultura IPB University dari bulan Maret 2023 hingga Agustus 2023. Percobaan penelitian disusun dalam Rancangan Acak Kelompok (RAK) satu faktor, yaitu dosis pupuk kalium dengan lima taraf perlakuan yaitu 0 kg, 30 kg, 60 kg, 90 kg, dan 120 kg K2O per hektar. Tiap perlakuan diulang 4 kali sehingga terdapat 20 satuan petak percobaan. Dosis pupuk kalium menunjukkan hasil berpengaruh nyata dengan respon kuadratik pada peubah diameter batang utama, sedangkan pada peubah vegetatif lainnya tidak berpengaruh nyata. Pada komponen produksi dosis pupuk kalium berpengaruh nyata pada jumlah dan bobot umbi sehat, jumlah dan bobot umbi layak pasar, diameter umbi, dan tingkat kemanisan umbi 1 minggu setelah simpan. Nilai rata-rata dosis pupuk K2O optimum adalah 48,87 kg ha-1 atau KCl 81,45 kg ha-1 .
Keyword: Cylas formicarius, Karbohidrat non-biji, kemanisan umbi

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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