Judul: Pengaruh iklim terhada profitabilitas kentang (Solanum tuberosum) di sentra perkebunan kentang Cikajang-Garut
Abstrak: Potato has a vital role for the Indonesian economy. Potatoes demand will increase caused by population growth and changing consumption patterns in developing countries. Production of potato is influenced by soil water, while soil water is influenced by rainfall, temperature and sunshine duration. Soil water at each planting season varies because of differences in the amount of rainfall. By linking the influence of planting season with soil water availability, profitability of each planting season will be known. There are three Cikajang planting periods: January-April, May-August and September-December. The average potato yield in three planting seasons at Cikajang: January-April amounted to 21 tons/ha, in May-August to 20,2 tons/ha and September- December with average potato yield 17,5 tons/ha. The decrease of production was caused by decreased water availability during the dry season. Highest profitability of potato planting time in the period from January-April amounted to Rp.21,350,000 while May-August amounted to Rp.18,456,250 and the lowest in September-December of Rp.13,195,833.
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Judul: Perhitungan Limpasan Permukaan dan Evapotranspirasi berdasarkan Neraca Air pada Pertanaman Kentang (Solanum Tuberosum L.)
Abstrak: Ketersediaan air merupakan salah satu faktor yang mempengaruhi pertumbuhan, perkembangan serta produksi tanaman kentang. Tanaman kentang cukup banyak dibudidayakan di Indonesia. Tanaman kentang biasa dibudidayakan pada ketinggian lebih dari 1000 m dpl dengan tingkat kemiringan yang cukup tinggi. Kondisi ini mempengaruhi ketersediaan air untuk pertumbuhan tanaman kentang. Tujuan penelitian ini adalah menghitung kehilangan air melalui evapotranspirasi dan limpasan permukaan pada tanaman kentang dengan menggunakan neraca air. Penelitian dilakukan mulai bulan Desember 2009 sampai Maret 2010 di Kebun Percobaan Balitbiogen Pacet-Cipanas, Cianjur. Perhitungan kehilangan air pada tanaman kentang dilakukan dengan pendekatan neraca air dengan persamaan ETat+Rot = θt-1-θt+Pt, dimana θt = kadar air tanah hari ke t, θt-1 = kadar air hari ke t-1, dan ETat+Rot = kehilangan air karena evapotranspirasi aktual dan runoff hari ke t. Evapotranspirasi actual diasumsikan sebesar 4 mm/hari. Hasil penelitian ini menunjukkan bahwa kondisi dimana curah hujan tinggi, terjadi runoff yang besar karena kapasitas infiltrasi dan perkolasi yang terbatas, dan tetap terjadi evapotranspirasi. Hal ini dapat mengurangi kadar air tanah selama masa pertumbuhan tanaman kentang. Kadar air tanah yang lebih tinggi menghasilkan laju pertumbuhan tanaman kentang yang lebih tinggi walaupun jarak tanamnya lebih rapat. Di samping kadar air tanah, ukuran bibit sangat menentukan hasil panen kentang.
Keyword: Potato, Water balance, Evapotranpiration, Runoff, Soil water

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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