<p>Oven portabel-horisontal (4m x 8m x 4m) untuk pengovenan daun tembakau Virginia menjadi krosok fc (flue-cured) telah direkayasa di Balai Penelitian Tanaman Tembakau dan Serat, Malang, Indonesia. Konstruksi oven terdiri alas komponen dinding oven berisolasi (80cm x 200cm), kerangka dari besi siku dan bcsi U, kolektor surya datar (solar flat- collector) yang dipasang pada atap oven. Sistem pcmanas kompor Bros dengan pemanasan tidak langsung. Pengujian dilakukan pada bulan Agustus sampai dengan Oktober 2002 di Lombok Timur, Nusa Tenggara Barat. Model oven portabel-horisontal ini diharapkan dapat menghasilkan suhu niang oven yang seragam sehingga dapat digunakan untuk mengoven daun tembakau yang persentase masak optimalnya tinggi (90- 95%), hemat bahan bakar, dapat dipasang mendekati areal tanaman sehingga hemat ongkos angkut dan dapat menekan kerusakan pasca panen. Hasil penelitian menunjukkan rata-rata selisih suhu ruang atas dan ruang bawah, serta ruang sebclah kanan dan sebelah kiri, masing-masing 2.53°C dan 2.30°C sedangkan selisih kelembaban udara pada posisi yang sama masing-masing hanya 4.55% dan 3.64%. Kadar gula krosok yang dihasilkan berkisar antara 17.19-19.47% dan nikotin 3.16-3.73%. Konsumsi minyak tanah 1.09 l/kg krosok atau 1.16 l/kg krosok jika tanpa kolektor surya dan hanya 40.92% dibanding oven biasa yang memeriukan 2.39-2.80 l/kg krosok. Kolektor surya datar menyumbang 952 625 kJ setara 28.24 I minyak tanah atau 5.80% dari konsumsi minyak tanah, meskipun alat ini memeriukan 17.16% dari total investasi oven. Panas yang hilang melalui dinding karena konduksi hanya mencapai 3.57%, lebih rendah dibanding kehilangan panas pada dinding bata yang mencapai 12.7% - 16.0%. Hasil grading krosok menghasilkan harga jual rata-rata Rp. 12.275/kg kosok, sedangkan hasil analisis ekonomi menunjukkan rasio BC = 1.29; NPV = Rp. 41 962 590 dan IRR = 51.83% atau masih membei peluang keuntungan dan pengembalian kredit. Hasil perhitungan simulasi jika digunakan oven horisontal sederhana dengan harga Rp. 8 000 000 tiap unit, harga krosok Rp. 10 000, Rp. 12 500, dan Rp. 15 000 tiap kg dan harga minyak tanah Rp. 1 000, Rp. I 250 dan Rp. I 500 tiap liter masih memberi indikasi peluang keuntungan dan pengembalian kredit. Konstruksi oven akan lebih sederhana jika digunakan kerangka kayu dan tanpa kolektor surya.</p><p>Kata kunci : Nicotiana tabacum, L, tembakau, prosesing, oven, portabel- horisontal, kolektor surya, analisis energi, mutu krosok, aspek ekonomi</p><p> </p><p><strong>ABSTRACT </strong></p><p><strong>Engineering of horizontal-potabel curing-barn of Virgi¬ nia tobacco curing</strong><br /><br />Engineeing of the horizontal-portable curing-barn (4m x 8m x 4m) of Virginia tobacco curing lo produce Virginia fc (flue-cured) tobacco conducted in Indonesian Tobacco and Fibers Crops Research Institute, Malang, Indonesia. The curing-bam construction consisted of portable isolation wall, metal frame from L and U iron-bar and flat solar collector which was installed in curing-bam roof. Bros buner and air indirect heating system were used. This curing-bam was tested in East Lombok, West Nusa Tenggara on virgina tobacco harvested in August to October 2002. This horizontal-portable curing-bam was expected to be able to<br /><br />96 <br /><br />produce the homogen temperature and humidity in all space of the curing- bam so that it is suitable for curing the harvesting tobacco leaves which high percentage of mature leaves (90-95%), fuel efficienct and liable to be constructed near tobacco plant area, so that it can decrease the transpotation cost and postharvest damage. The result of the research showed that there were significant difference between above-space and lower-space, let-space and right-space, even it was only 2.53°C and 2.30°C, respectively. The same position for air humidity, 4.55% and 3.64%, respectivelly. Kerosene fuel consumption 1.09 I each kg cured- leaves or 1.16 I each kg cured leaves if without lat solar collector, lower than farmers conventional curing-bam which consumpt 2.39-2.80 I each kg cured-leaves. Flat solar-collector contributed 952 625 Id only or 5.80% of kerosene consumption or equal lo 28.24 I kerosene, even though this equipment needed 17.16% of total curing-bam in vestal ion Heat conduction lost through the portable wall only 3.57%, lower than brickwall conventional curing-bam which reach 12.7-16.0%. Result of the cured-leaves grading gave the average price Rp 12 275,- each kg cured- leaves and economic analysis showed that BC-ratio-1.29, NPV-41 962 590 and IRR=51.83% or still gave the profit chance and ability to pay the capital interest. Result of simulate calculation by simple construction curing-bam, Rp. 8 000 000 price each unit, still gave BC-ratio above one percent. This indicated the profit chance and ability to pay the capital interest. In this simulate calculation three price of cured-leaves and kerosene was used, as followed Rp. 10 000, Rp. 12 500, and Rp. 15 000 each kg cured leaves, and Rp. I 000, Rp. 1 250 and Rp. I 500 each liter of kerosene, respectivelly. The construction of the curing-bam will be simpler if using wood frame and without lat solar collector.</p><p>Key words : Nicotiana tabacum, L., tobacco, processing, oven, horizontal- portable curing-bam, lat solar-collector, energy analysis, cured-leaves grade, economical-aspect</p>
Effects of Herbicide Application Timing and Tillage System on Tobacco Plant (Nicotiana tabacum L.)
