Judul: Effects of Plant Density and Nodes Cutting on Sweetpotato (Ipomoea batatas L.) Growth and Yield in Polybag in Context of Urban Farming
Abstrak: Ubi jalar (Ipomoea batatas L.) memiliki potensi dalam pertanian perkotaan. Stek mini dapat menurunkan kebutuhan bahan tanam. Kerapatan tanam yang lebih tinggi dapat meningkatkan efisiensi lahan. Penelitian ini bertujuan untuk menentukan jumlah buku bibit dan kerapatan tanam yang optimal bagi pertanian kota yang efisien. Penelitian dilakukan antara Mei - Oktober 2021 di Setu, Tangerang Selatan. Penelitian dirancang dengan split plot-rancangan kelompok lengkap teracak (SP-RKLT). Faktor pertama adalah jumlah buku bibit dengan taraf 2, 4, dan 6 buku. Faktor kedua adalah kerapatan tanam dengan 1, 2, dan 3 stek per polybag. Hasil menunjukkan bahwa bibit dengan buku yang lebih banyak memiliki pertumbuhan batang, daun, dan buku awal yang lebih baik sampai 8 MST. Perlakuan 1 stek per polybag memberikan pertumbuhan akhir individu tinggi namun perlakuan 2 dan 3 stek per polybag memberikan pertumbuhan per polybag dan hasil umbi yang paling tinggi., Sweet potato (Ipomoea batatas L.) has potential for efficient urban farming. Mini cutting can reduce plant material needs. High plant density can lead to more efficient land use. This research aims to deduce the most optimal node cutting and plant density for efficient urban farm. Research was done from May to October 2021 in Setu, Tangerang Selatan. This research is designed with split-plot randomized complete block design (SP-RCBD). First factor is node cutting with treatment 2, 4, and 6 node each cutting. Second factor is plant density with treatment 1, 2, and 3 cutting each polybag. Result shows that cutting with more node have better early growth until 8 weeks after planting. Plant density of 1 plant per polybag gives best individual plant late growth while 2 and 3 plant per polybag give better per polybag growth and tuber yield.
Keyword: jumlah buku bibit, kerapatan tanam, pertanian kota, polybag, ubi jalar, node cuttings, plant density, sweet potato, urban farming

Judul: The Growth and Tuber Yield of Sweetpotato (Ipomoea batatas L.) Ase Kapas at Various Rates of Nitrogen Fertilizer
Abstrak: Ubijalar merupakan tanaman pangan penting di Indonesia. Produktivitas ubijalar dapat dipengaruhi oleh pemupukan. Tujuan penelitian ini yaitu menentukan dosis nitrogen bagi pertumbuhan dan produksi ubijalar Ase Kapas. Penelitian dilakukan pada bulan Januari sampai Juli 2020 di Kebun Percobaan Cikabayan IPB dengan rancangan kelompok lengkap teracak dengan 3 ulangan. Dosis N yang diaplikasikan yaitu 0; 22,5; 45; 67,5; dan 90 kg ha-1 . Bahan tanam yang digunakan yaitu bagian stek pucuk. Curah hujan selama penelitian cenderung tidak sesuai dengan kondisi optimal pertumbuhan ubijalar. Pada tanah dengan kandungan nitrogen berstatus sedang (0,29% setara dengan 174 kg ha-1 ), dosis N tidak berpengaruh signifikan terhadap perubahan panjang dan diameter sulur, jumlah daun dan cabang, panjang dan diameter umbi, serta bobot basah dan kering umbi dan brangkasan. Pada tanah dengan kandungan N total sedang, dosis 0 kg N ha-1 dapat diaplikasikan untuk mendukung pertumbuhan dan produksi yang baik bagi ubijalar klon Ase Kapas., Sweetpotato is an essential crop plant in Indonesia. The productivity of the sweetpotato could be affected by fertilization. The objective of this research is to assess optimal nitrogen rate for growth and root yield of sweetpotato Ase Kapas. The experiment was conducted at IPB University experimental field Cikabayan from January to July 2020 used randomized complete block design with 3 replications. The level of nitrogen fertilizer consists of 0; 22,5; 45; 67,5; and 90 kg ha-1 . The planting material is the vine cuttings. The rainfall during this experiment tends to be insufficient as climate requirements. In the soil with moderate N content (0.29% equal to 174 kg ha-1 ), nitrogen had no significant effect on the growth of length and diameter of main stem, the amount of leaves and secondary stems, length and diameter of storage roots, wet- and dry-weight biomass of storage roots and aboveground part. In the soil with a moderate N total, dose of 0 kg N ha-1 could be applied to support good growth and yield of sweetpotato clone Ase Kapas.
Keyword: produktivitas, suplai nitrogen, umbi, Urea, nitrogen supply, storage root, productivity

Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
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