Judul: Variations of organic carbon content as related to the difference in water table levels of peatlands cultivated for plantation commodities.
Abstrak: Peatlands are important sinks for the atmospheric carbon (C) and play major roles in the global C cycle. In virgin forest, C sink and emission is balanced. During land reclamation, this balance is disturbed by drainage channel construction which affects water table level and other consequences. It is therefore important to study the effects of drainage channel construction on the distribution of soil C content and its dynamics. This research aimed at to evaluate: (1) the effects of distance to the drainage channel in water table level, (2) the effects of water table level on organic-C content, and (3) the relationships among organic-C content with the characteristics of peatland based on land use time for cultivation of plantation commodities. The research was conducted in Bengkalis District, Riau Province from January until June 2011. The characteristics of peatland observed were bulk density, ash content, peat thickness, and water table level. The results showed that the closer the distance from drainage channel, the deeper was the water table level. Two patterns of the relationship between water table level and organic-C content were observed. The first pattern at 50-100 cm layer was the increase in organic-C with the decrease in water table level up to water table level about -46.5 cm. The second at 0-50 cm layer was the opposite of first pattern up to water table level about -49 cm. Peatlands of the study area were characterized by organic-C content of 55.16-57.28%, bulk density of 0.04-0.11 g/cm3, ash content of 1.25-4.90%, water content of 492.54-1226.81%, and degree of peat maturity of fibric, hemic and sapric with fibre content of 11.67-35%. Generally, at 0-50 cm layer organic-C content was influenced significantly by ash content, with at 50- 100 cm layer was by ash content and water table level.
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Judul: Subsidence and Percentage of CO2 Emission from the Decomposition to Subsidence of Peatland on Palm Oil Plantations
Abstrak: The drainage system on peatlands is aimed to eliminate limiting factors that can inhibit the growth of oil palm plantations. On the other side, peatland drainage practices will cause peat subsidence and it is associated with CO2 emissions from peatlands. Subsidence method is one of the methods commonly used in the approach to calculate CO2 emissions. The peat subsidence process consists of consolidation, compaction, and decomposition. Previous research resulted in emission data of 100 tons CO2/ha/year, of which 92% of the subsidence is considered as decomposed peat, and 8% is the components of compaction, soil respiration (autotroph and heterotroph). The percentage of decomposition to compaction-consolidation in the previous study was overestimated. The research was conducted on the oil palm plantation of Koto Gasib Village, Siak Regency, Riau Province. From January 2019 to January 2020. The study was carried out on oil palm plantation blocks on peatlands that have been controlled drained with a canal system to maintain water levels. Observational data were collected from 6 subsidence stick, 3 dipwells, 3 peat profiles, and LiCor 8100A automatic chamber. The observation interval for the observation of bulk density, subsidence, C-Organic and ash content every 3 months, while for the water level using the monthly average and every 30 minutes for CO2 flux. Peat analysis was conducted at the Laboratory of Chemistry and Soil Fertility, Department of Soil Science and Land Resources, IPB. The purpose of this study were to observe the rate of subsidence of tropical peatlands in oil palm plantations at various ages of oil palm plants, and to determine the percentage of decomposition of peat material from the subsidence rate. Subsidence was measured at adjacent oil palm planting blocks at 9, 12, and 17 years of age, with a peat thickness of about 5 m, and the land had been drained for 10, 13, and 18 years, respectively (one year prior to planting). Peat decomposition (heterotrophic respiration) is considered as actual CO2 emission compared to the calculated emission from subsidence which is considered as potential CO2 emission from the calculation of the subsidence method. Analysis of peat fiber at the research site generally shows that the deeper the surface of the peat, the higher the fiber volume with the average fiber at a depth of 0-10 cm 25.3% and classified into hemic peat. The peat density analysis using the kubiena box showed that the average density of peat at a depth of 0-20 cm in the three blocks observed was 0.134 g/cm3. Peat ash content shows accumulation on the peat surface as a result of the decomposition process of peat material, with an average of 5.83% and 2.31% at depths of 0-10 and 10-20 cm, respectively. Meanwhile, the organic C content of peat showed an average of 55.64% at a depth of 0-20 cm. The average subsidence rate for oil palm plantations on tropical peatlands 10-18 years after controlled drainage is 2.47 ±0.76 cm/year. Peatland subsidence is higher in older oil palms due to higher plant load and root density. There is a bouncing back phenomenon or an increase in the peat
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Judul: Infeksi Virus Parainfluenza Pada Anjing
Abstrak: Virus parainfluenza anjing termasuk famili Paramyxoviridae, berbentuk pleomorf dengan ukuran bervariasi (bergaris tengah antara 100-500 nm), berpembungkus peka ether, berisi genom RNA dan secara serologis mempunyai kesamaan dengan virus SV-5 kera; dikenak sebagai salah satu kausa penting dari sindrom "kennel cough". Infeksinya dapat mengenai anjing semua umur yang belum pernah terinfeksi atau mendapatkan vaksinasi mengakibatkan gejala klinis ringan yang terbatas pada traktus respirasi atu infeksi yang secara klinis tidak memperlihatkan gejala nyata. Gejala klinis yang nampak setelah masa inkubasi (1-5 hari) terlewati berupa batuk yang tidak berat selama beberapa hari, berbagai tingkat tonsilitis dan pharyngitis dan kadang-kadang ditemukan kenaikan temperatur rektal antara 1-2 derajat C dari temperatur normal rat-rata. Anjing terinfeksi mengandung virus pada traktus respirasi bagian atas dan bawah serta limfonoduli sampai hari ke 9 setelah infeksi. Penyebaran virus antar anjing terjadi secara aerogen.
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