Judul: Faktor iklim dan tanaman ubijalar: Analisis pola tanam dan profit usaha tani di Desa Cikarawang
Abstrak: Sweet potato is one of the crop that can be used by Indonesian people as a staple or a processed foods. Sweet potato becomes the main commodity in Cikarawang village. Cikarawang has average rainfall of about 314 mm/month, average monthly temperature 25 oC to 28 oC, and average monthly sunshine duration of 64%. Cikarawang has three cropping patterns; cropping pattern A: sweet potato (month January-April) – sweet potato (May-August) – paddy (September-December), cropping pattern B: sweet potato (January-April) – peanut (May-August) – paddy (September-December), and cropping pattern C: only plants sweet potato all years. There were differences in productivity, production costs, and profitability in the three types of cropping pattern in Cikarawang. The analysis showed that temperature, rainfall, and sunshine duration affect the production costs and profit. A high rainfall, low temperature, high surplus and runoff caused high production costs. High production mostly commonly occurred in period of January-April. The survey indicated that cropping pattern A is the most profitable resulted from highest profit.
Keyword: Bogor Agricultural University (IPB), sweet potato, profit, cropping pattern, climate factor

Judul: Economic Efficiency Analysis of Sweet Potato Farming in Cikarawang Village, Dramaga District, Bogor Regency
Abstrak: Desa Cikarawang merupakan salah satu daerah sentra produksi ubi jalar di Kecamatan Dramaga. Produktivitas ubi jalar di Desa Cikarawang cenderung menurun tiap tahunnya. Produksi dan produktivitas ubi jalar yang menurun diduga disebabkan oleh alokasi input produksi yang tidak optimal. Produksi ubi jalar yang rendah akan berpengaruh terhadap pendapatan yang diterima oleh petani. Penelitian ini dilakukan untuk menganalisis pendapatan usahatani ubi jalar, menganalisis faktor-faktor yang memengaruhi produktivitas ubi jalar, dan menganalisis efisiensi penggunaan input produksi yang optimal. Metode analisis data yang digunakan yaitu analisis pendapatan usahatani, analisis regresi linear berganda, dan metode Nilai Produk Marginal. Hasil penelitian ini menunjukkan bahwa usahatani menguntungkan karena pendapatan bernilai positif dan R/C ratio lebih besar dari satu. Faktor-faktor yang berpengaruh secara positif dan signifikan terhadap produktivitas ubi jalar adalah pupuk kandang dan pestisida cair. Faktor produksi yang belum efisien pada usahatani ubi jalar yaitu pupuk kandang dan pestisida cair sehingga perlu untuk ditambah. Kata kunci: analisis pendapatan, efisiensi ekonomi, NPM, produktivitas, R/C ratio, Cikarawang Village in Dramaga District is one of the main sweet potato production areas. The productivity of sweet potatoes in Desa Cikarawang tends to decrease each year. The decreasing production and productivity of sweet potatoes are suspected to be caused by suboptimal allocation of production inputs. The low production of sweet potatoes will affect the income received by farmers. This research was conducted to analyze the income from sweet potato farming, analyze the factors affecting sweet potato productivity, and analyze the efficiency of optimal production input usage. The data analysis methods used were farm income analysis, multiple linear regression analysis, and the Marginal Product Value method. The results of this study indicate that farming is profitable because the income is positive and the R/C ratio is greater than one. Factors that positively and significantly affect sweet potato productivity are manure and liquid pesticides. The production inputs that are not yet efficient in sweet potato farming are manure and liquid pesticides, which therefore need to be increased.
Keyword: produktivitas, R/C ratio, analisis pendapatan, efisiensi ekonomi, NPM

Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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