Judul: Pengembangan Sistem Informasi Iklim Berbasis Pemodelan Dinamika Populasi Untuk Rencana Pengendalian Penggerek Batang Padi Kuning
Abstrak: Penggerek Batang Padi Kuning atau lebih lanjut disebut PBK merupakan salah satu hama utama tanaman padi yang memiliki intensitas serangan cukup tinggi pada areal sentra produksi padi, khususnya di wilayah Jawa Barat. Faktor iklim merupakan salah satu faktor eksternal lingkungan yang sangat berpengaruh terhadap pola dinamika populasinya. Oleh karena itu, sistem informasi iklim untuk prediksi serangan hama PBK akan menjadi sangat penting bagi upaya pengendalian dini PBK pada masa mendatang. Tujuan penelitian ini adalah untuk menyusun model prediksi dinamika populasi hama PBK dibawah skenario perubahan iklim jangka pendek menggunakan Model DYMEX di wilayah Indramayu, Jawa Barat. Selain itu, pemodelan dikembangkan lebih lanjut untuk menduga potensi resiko kehilangan hasil padi serta menentukan manajemen dalam rencana pengendalian dini PBK yang efektif pada masa mendatang berdasarkan hasil keluaran model. Pemodelan PBK membutuhkan dua input komponen utama, yaitu paramater iklim dan suhu ambang bawah perkembangan (To) untuk menggambarkan siklus hidup PBK mulai dari tahap telur, larva, pupa hingga dewasa (imago). Penambahan input skenario perubahan iklim jangka pendek (RCP 2.6 dan RCP 8.5) dilakukan berdasarkan proyeksi perubahan suhu udara dan curah hujan musiman untuk memprediksi kondisi iklim pada tahun 2016-2035. Fungsi kerusakan tertinggi atau potensi resiko kehilangan hasil padi diasumsikan oleh serangan larva PBK instar 3 dan 4. Penentuan puncak dan jumlah populasi spesifik imago digunakan sebagai acuan untuk menentukan ambang kendali PBK. Rekomendasi dan manajemen pengendalian PBK dalam menerapkan integrasi sistem PHT menggunakan pendugaan periode perkembangan telur PBK dibawah skenario perubahan iklim. Uji kalibrasi dan validasi model menunjukkan adanya nilai koefisien determinasi (R2) antara hasil prediksi dan observasi pada wilayah kajian masing-masing sebesar 0.74 dan 0.77 dengan variansi data yang homogen (Fhitung < Ftabel, pada α = 0.05, yaitu sebesar 0.0048 < 0.926 dengan hasil Pvalue = 0.000). Hal tersebut dapat memberikan gambaran bahwa dinamika populasi PBK di wilayah Indramayu dipengaruhi cukup kuat oleh faktor iklim serta perilaku dan kemampuan model dapat dinilai cukup baik. Pada kondisi iklim periode baseline terdapat kecenderungan puncak kelimpahan populasi terjadi ketika adanya perubahan intensitas curah hujan pada saat musim peralihan yang didukung oleh suhu dan kelembaban udara yang ideal. Pada penerapan skenario perubahan iklim, model mampu memprediksi adanya kecenderungan peningkatan jumlah populasi, jumlah generasi per tahun, pergeseran puncak kelimpahan populasi serta potensi resiko kehilangan hasil pada masa mendatang. Dalam upaya mengurangi penggunaan pestisida yang berlebihan, rekomendasi dan manajemen pengendalian PBK dapat dilaksanakan 3 hari setelah terdapat tangkapan imago pada light trap dengan acuan ambang kendali mencapai >24 ngengat/malam. Hal ini tentunya dapat menjadi suatu metode baru dalam pengembangan sistem informasi iklim untuk meningkatkan strategi pengendalian PBK serta sebagai bentuk adaptasi terhadap dampak perubahan iklim sejak dini khususnya di wilayah Indramayu.
Keyword: DYMEX, skenario perubahan iklim, penggerek batang padi kuning, kehilangan hasil

Judul: Pemodelan Fenologi Populasi Penggerek Batang Padi Kuning Scirpophaga incertulas (Walker) Berbasis Pengaruh Iklim
Abstrak: West Java province is the highest of rice production area in Indonesia, contributing an average of national rice production about 17.4% in 2009 to 2012. Rice production can be maintained or enhanced if we have a great capability to protect rice from pests’ infestation. In 1995, the population of rice white stem borer (WSB) Scirpophaga innotata (Walker) decreased, while the population of the rice yellow stem borer (YSB) Scirpophaga incertulas (Walker) increased to 30%. Since 1995, YSB was more dominant than WSB, with population of more than 90%. Based on the report from Directorate of Food Crop Protection, some areas in the West Java in particular of North Coastal region has a total area of high annual infestation compared to other regions, reaching ± 10 to 12 thousand ha. High infestation of YSB is suspected as a result from transition of rice varieties. Furthermore, climatic might have strong influence on population dynamics of rice stem borer. Understanding relationship between climatic factors and life cycle and population dynamics of YSB is important for long- and short term management strategies, as control measures to reduce production and economic losses. This research utilized DYMEX software and aims to develop a population dynamic model of YSB and to assess model's ability to predict abundance and population peak of YSB under climate change scenario SRES A1FI and B1. Modeling the YSB requires two major components: climate parameter and lower developmental threshold temperatures (To) to describe life cycle of YSB from the egg, larva, pupa, and adult stages. DYMEX also describe development, mortality, transfer of individuals from one to the next life stages, fecundity and reproduction of YSB. The coefficient of determination (R2) of calibration models between predictions and observations showed a strong positive correlation of 0.72. Model validation could well predict the peak population, with R2 of 0.42. The simulations showed that the trend of population peaks occur at high rainfall i.e. in March to April, July to September, and November to December. The model predicted YSB population in the Sukamandi and Pusaka Negara reaches 3 generations per year, while in Kuningan 2 generations per year. Decrease in the population will affect the number generations of YSB in the three regions. Simulation models under climate change scenarios SRES A1FI and B1 showed differences in the sensitivities. Trend of YSB population is increasing in the regions Pusaka Negara and Kuningan and decreasing in region Sukamandi. Under changing climate, environment conditions in Pusaka Negara and Kuningan become more suitable for the proliferation YSB, allowing an increase in the number of generations per year. The level of model accuracy can still be improved by exploring more variables to include interactions between YSB and host plant (paddy) and the natural predators parasitism against the YSB. This makes model becomes more complex but may reflect better condition of YSB populations in the field. Further model improvement could be facilitated by be integrating DYMEX and CLIMEX software to determine the distribution of species in relation to climatic conditions. This models integration can simulate regional risks and determine whether a site could potentially be
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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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