https://talenta.usu.ac.id/jpt/issue/feedJurnal Online Pertanian Tropik2025-05-21T06:44:21+07:00Benny Hidayatbendayat@gmail.comOpen Journal Systems<p style="text-align: justify;"><strong>Jurnal Online Pertanian Tropik (JOPT)</strong> is a peer-reviewed journal of the Agriculture Postgraduate Study Program, Universitas Sumatera Utara. Published in Indonesian and English three times a year (April, August, December) with 20 articles per issue, it covers tropical agricultural studies. Hosted by TALENTA Publisher since 2019, JOPT is accredited by the Ministry of Technology Research and Higher Education (No. 21/E/KPT/2018).</p> <p style="text-align: justify;"><strong>ISSN (Print/Online): 2356-4725 / 2655-7576</strong></p>https://talenta.usu.ac.id/jpt/article/view/17252Quality Characteristics of Clove Leaf Essential Oil Based on Leaf Pretreatment Using the Steam Distillation Method2025-04-24T20:27:29+07:00Ida Ayuida.ayuwidhiantari@unram.ac.id<p>Cloves are a plant that is often used as an ingredient in cooking or as an addition to cakes. The clove plant is not only used for its cloves, but its leaves can also produce great benefits. Some of the benefits of clove leaves include that they can be used for various types of treatment, including cough medicine, stomach ache medicine, and toothache medicine. The quite diverse chemical content in clove leaves provides quite open opportunities for use, one of which is being used as a raw material for producing essential oils. The aim of this research is to determine the suitability of the quality of the essential oil obtained in the form of yield, specific gravity, refractive index and solubility in 90% alcohol in accordance with the Indonesian National Standard (SNI) produced from clove leaves using the steam distillation method. The research method used in this research is an experimental method by conducting experiments in the laboratory. The treatments used were whole clove leaves (S1), clove leaves chopped at 50% (S2) and 25% (S3) of the total length of clove leaves, and crushed clove leaves (S4). The parameters of this research are yield, specific gravity, refractive index, and solubility in 90% alcohol. The results of the research showed that the best treatment was obtained from clove leaf samples chopped at 25% of the total leaf length which had the highest average yield and specific gravity, namely 2.88% and 1.061 g/ml. The refractive index value and the average solubility of clove leaf essential oil in each sample treatment met the Indonesian national standard (SNI 06-2387-2006).</p>2025-05-21T00:00:00+07:00Copyright (c) 2025 Jurnal Online Pertanian Tropikhttps://talenta.usu.ac.id/jpt/article/view/16245Optimum Doses of N, P, And K Fertilizers For Samosir Shallot Varieties in the Plains of the Lake Toba Region2024-08-25T21:28:05+07:00Razalirazali@usu.ac.idDolly Sojuangan Siregarregar_dolly@yahoo.com<p>The surrounding plain of Lake Toba is well known as a shallot producing area in North Sumatra Province. Samosir variety is the mainstay variety of shallot farmers in this area. One of the efforts to increase the productivity of shallot variety Samosir is the application of fertilizer. The amount of N, P and K nutrients given to the Samosir variety shallot plants must be appropriate. This study aims to obtain the optimum dose of N, P and K fertilizers in the cultivation of shallot varieties Samosir planted in the rainy season in the plains around Lake Toba. This study consisted of 3 parallel experiments to determine the optimum N, P, K fertilization with a non-factorial randomized group design (RAK). P<sub>2</sub>O<sub>5</sub> and K<sub>2</sub>O fertilizers were applied 100% in the N rate experiment, N and K<sub>2</sub>O fertilizers were applied 100% in the P rate experiment, and N and P<sub>2</sub>O<sub>5</sub> fertilizers were applied 100% in the K rate experiment. Each experiment consisted of 5 levels, namely 0, 50, 100, 150, and 200% of the reference dose and each treatment was repeated 3 times so that there were 45 experimental plots. Parameters were: fresh weight of tubers and crowns at the end of the vegetative period, crown weight and wind-dried harvest tubers. The results obtained the optimum dose of N and P fertilizer recommendations are 154.22 kg N ha<sup>-1</sup> and 126.62 kg P<sub>2</sub>O<sub>5</sub> ha<sup>-1</sup>. For K fertilization does not give a quadratic response pattern so there is no optimum dose.</p>2025-05-21T00:00:00+07:00Copyright (c) 2025 Jurnal Online Pertanian Tropik