Many protocols suggest to dry biomass in blue carbon ecosystems at 60 degree celsius, such as 'coastal blue carbon-methods for assessing carbon stocks and emissions factors in mangroves, tidal salt marshes, and seagrass meadows'. Does anybody know why 60 rather than 105 degree celsius is suggested? Thank you.
Dear colleague
This is probably due to the fact that this method is widely used to estimate the biomass usable as feed (fodder or other), and that often the determination of dry matter is followed by chemical, enzymatic, digestibility, etc. analyses. Drying at 60°C prevents or at least limits the degradation of the most fragile compounds. However, most analytical laboratories dry subsamples at 105°C to determine the true dry matter content, before mineralizing them in the furnace to determine organic and mineral matter levels.
Regards
The most important thing is that all water is removed without degrading the biomass :)
Dear Xiaoguang Ouyang,
The temperature around 60 °C is used to evaporate water but keep minerals and carbon. When you use «low» drying temperatures, you need to check if the samples have a constant weight. So, you need to weigh them twice at few days apart. At constant weight, these samples are ready for more laboratory processing and analyzing.
At 105 °C, it is faster to evaporate water and dry your samples. However, you cannot do nitrogen determination since nitrogen volatilizes above 70 °C. Usually, we do both methods, one for N chemical analyses (about 60 °C), and one for water content and express the results on a dry weight basis (105 C).
Kind regards,
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