![]() Simulating SOC changes in 11 land use change chronosequences from the Brazilian Amazon with RothC and Century models [An article from: Agriculture, Ecosystems and Environment] $10.95 This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: Land use and land cover changes in the Brazilian Amazon have major implications for regional and global carbon (C) cycling. Cattle pasture represents the largest single use (about 70%) of this once-forested land in most of the region. The main objective of this study was to evaluate the accuracy of the RothC and Century models at estimating soil organic C (SOC) changes under forest-to-pasture conditions in the Brazilian Amazon. We used data from 11 site-specific 'forest to pasture' chronosequences with the Century Ecosystem Model (Century 4.0) and the Rothamsted C Model (RothC 26.3). The models predicted that forest clearance and conversion to well managed pasture would cause an initial decline in soil C stocks (0-20cm depth), followed in the majority of cases by a slow rise to levels exceeding those under native forest. One exception to this pattern was a chronosequence in Suia-Missu, which is under degraded pasture. In three other chronosequences the recovery of soil C under pasture appeared to be only to about the same level as under the previous forest. Statistical tests were applied to determine levels of agreement between simulated SOC stocks and observed stocks for all the sites within the 11 chronosequences. The models also provided reasonable estimates (coefficient of correlation=0.8) of the microbial biomass C in the 0-10cm soil layer for three chronosequences, when compared with available measured data. The Century model adequately predicted the magnitude and the overall trend in @d^1^3C for the six chronosequences where measured @d^1^3C data were available. This study gave independent tests of model performance, as no adjustments were made to the models to generate outputs. Our results suggest that modelling techniques can be successfully used for monitoring soil C stocks and changes, allowing both the identification of current patterns in the soil and the projection of future conditions. Results were used and discussed not only to evaluate soil C dynamics but also to indicate soil C sequestration opportunities for the Brazilian Amazon region. Moreover, modelling studies in these 'forest to pasture' systems have important applications, for example, the calculation of CO"2 emissions from land use change in national greenhouse gas inventories. ![]() Byer of Maine Model A101820 Barbados Hammock Single Ruby Red $89.95 It's a hammock, plain and simple and a really good one at that. Very comfortable, sturdy and stable, and no waffle print on your face when you fall asleep in it! ![]() 1/48 A-4M Skyhawk "Brazilian Navy" $32.95 Hasegawa models are traditional plastic assembly models that require glue to put them together. They come with decals, but many aircraft modelers also use their own paint to create unique or more authentic schemes for their aircraft models. The Hasegawa line of precision aircraft and military vehicle models are precision made in Japan and are treasured as highly detailed and realistic models. |
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