Effect of rice variety on methane emission from an Indonesian paddy field

Variations in CH₄ emission from a Sumatra paddy field in which 8 popular modern varieties in Indonesia were grown were compared in the 1994/1995 rainy season. Total amounts of CH₄ emitted during the period of rice growth were in the ranges of 32.6-41.7 and 51.3–64.6 g CH₄ m^-2 for the plots amended with chemical fertilizer only and those amended with both rice straw and chemical fertilizer, respectively. The mean CH₄ emission rate was highest in the plot with the variety Bengawan solo and lowest in the plots with the varieties Atomita-4 and Way seputih among the plots which received chemical fertilizer, while highest in the plot with Way seputih and lowest in the plot with Bengawan solo among the plots amended with both rice straw and chemical fertilizer. The increase in the mean CH₄ emission rates by rice straw application was higher for the plots planted with Way seputih (1.98 times) and Atomita-4 (1.77 times) than for the plots with Bengawan solo (1.23 times) and IR-64 (1.35 times). The plots with Walanai and Cisanggarung recorded intermediate mean emission rates and the increase in CH₄ emission by rice straw application was also intermediate (1.57–1.64 times). It was noteworthy that Way seputih and Atomita-4 were derived from the variety Cisadane, Bengawan solo and IR-64 from the variety IR-54, and Walanai and Cisanggarung from the varieties IR-36 and Pelita 1-1, respectively.

The amounts of CH. emitted for 1 kg grain production ranged from 53 (Atomita-4) to 74 (Kapuas and Walanai) and from 89-93 (IR-64, Bengawan solo, and Atomita-4) to 121 (Kapuas) g CH₄ kg^-1 of grain for the plots amended with chemical fertilizer and those amended with rice straw and chemical fertilizer, respectively.     

Estimates of forest biomass in the Brazilian Amazon: New allometric equations and adjustments to biomass from wood-volume inventories

Uncertainties in biomass estimates in Amazonian forests result in a broad range of possible magnitude for the emissions of carbon from deforestation and other land-use changes. This paper presents biomass equations developed from trees directly weighed in open forest on fertile soils in the southern Amazon (SA) and allometric equations for bole-volume estimates of trees in both dense and open forests. The equations were used to improve the commonly used biomass models based on large-scale wood-volume inventories carried out in Amazonian forest. The biomass estimates from the SA allometric equation indicate that equations developed in forests on infertile soils in central Amazonia (CA) result in overestimates if applied to trees in the open forests of SA. All aboveground components of 267 trees in open forests of SA were cut and weighed, and the proportion of the biomass stored in the crowns of trees in open forest was found to be higher than in dense forest. In the case of inventoried wood volume, corrections were applied for indentations and hollow trunks and it was determined that no adjustment is needed for the form factor used in the RadamBrasil volume formula. New values are suggested for use in models to convert wood volume to biomass estimates. A biomass map for Brazilian Amazonia was produced from 2702 plots inventoried by the RadamBrasil Project incorporating all corrections for wood density and wood volume and in factors used to add the bole volume of small trees and the crown biomass. Considering all adjustments, the biomass map indicates total biomass of 123.1 Gt (1 Gt = 1 billion tons) dry weight (aboveground + belowground) for originally forested areas in 1976 in the Brazilian Legal Amazon as a whole (102.3 Gt for aboveground only) at the time of the RadamBrasil inventories, which were carried out before intensive deforestation had occurred in the region. Excluded from this estimate are 529,000 km² of forest lacking sufficient RadamBrasil inventory data. After forest losses of 676,000 km² by 2006 – not counting 175,000 km² of this deforested area lacking RadamBrasil data – the estimated dry biomass stock was reduced to 105.4 and 87.6 Gt (aboveground + belowground and only above-ground). Thus, in 2006 the carbon storage in forested areas in Brazilian Amazonia as a whole will be around 51.1 Gt (assuming 1 Mg dry biomass = 0.485 Mg C). Biomass estimates by forest type (aggregated into 12 vegetation classes) are provided for each state in the Brazilian Legal Amazon.     

The relation between farm specific factors and prevalence of Clostridium difficile in slaughter pigs

Foodborne ingestion through pork products of Clostridium difficile has been suggested a possible route of transmission of C difficile from pigs to humans. To determine whether C. difficile bacteria are present in the intestines of slaughter pigs, rectum contents of 677 slaughter pigs from 52 farms were collected at the slaughterhouse. Data on farm specific factors were collected and the association of these factors with the presence of C. difficile in pig herds from 39 farms was assessed. The prevalence of C. difficile and the ribotypical diversity that were found in this study were much higher than previously reported in literature, with an overall C. difficile prevalence of 8.6% (58/677). Sixteen distinct C. difficile ribotypes were identified, predominantly type 078 (31.0%, 18/58). This type is also commonly found in humans with C. difficile infection (CDI). Both on individual pig level and on herd level, no significant difference between the prevalence of C. difficile in pigs derived from conventional or organic farming types was detected. Farm system, size, and presence of other animal species on the farm did not result in significant different prevalences of C. difficile.     

Methane emission from an Indonesian rainfed paddy field

In relation to global warming, a great deal of attention has been paid to methane (CH4 ) emission from paddy fields. The amount of CH₄ emitted from paddy fields is now estimated to account for about 12% of the total CH₄ emission according to Prather et al. (1995). Harvested area of rough rice in Asia covered 1,320,000 km² in 1990 and 38% of the area was estimated to be maintained under rainfed conditions (IRRI 1991).     

Does the renal portal valve exist in a raptor species? A study aimed at further evaluating the mechanism of toxicity of diclofenac in vultures

Diclofenac has been responsible for the deaths of millions of vultures on the Asian subcontinent. While the pathology of toxicity is well described, the mechanism of toxicity remains elusive. However, it was postulated that toxicity could be related to the unique avian renal vascular structure known as the renal portal valve and that that diclofenac altered valve functionality with subsequent renal ischaemia. While plausible, the valva renalis portalis has only been described in a small number of other bird species such as the chicken (Gallus domesticus), the domestic duck (Anas platyrhynchos domesticus) and ostrich (Struthio camelus) but not a raptor. The aim of this study was to evaluate the renal anatomy and related vasculature of the Cape griffon vulture (Gyps coprotheres) (CGV), a species sensitive to the toxic effects of diclofenac, using gross anatomy, histology and vascular casting. The vasculature of the vulture was found to be almost identical to that of the domestic chicken with the valva renalis portalis present in the v. iliaca externa between the v. renalis renalis cranialis and the v. renalis caudalus. The valve was ring-shaped with finger-like processes and histologically was composed of smooth muscle. The valve was also well vascularized and was associated with a nerve plexus. Based on the findings of this study, the proposed mechanism of toxicity is anatomically possible.