in a soil texture analysis, the water-soaked soil sample must be placed in the oven at 105°C for 24 hours. if the oven cannot exceed 100°C, how long will the sample be left in the oven?
That's a trial and error method, ultimate objective is to obtain dried soil such that while weighing no more sticking takes place.
For clayey soils 24 hrs time period is not valid
You are worry about the water retain in the micropores of the soil. If you heat the soil until dry it, it should be ok as long it not gaing weith in the balance. If the sample are getting weight you should the sample directly from the oven into the balance dont wait until it get still because of the weight gaing in.
I don't think it is not proper to dry soil at 105°C before texture analysis, because some changes may occur in clay minerals during this process. In my opinion it is better to perform soil texture analysis in air-dried soil or, in fresh soil which is neither sticky nor dusty, as it was written by Sritama Chatterjee. But, a different subsample of soil should be dried in owen to determine moisture content. And this moisture content should be considered when weighting the soil sample for texture analysis (better option) or for recalculation of results of particle size distribution determination. E. g. if the soil contain 3% of water, we should weight about 20,6g instead of 20g. If we made analysis on 20g, we must recalculate results, remembering, that it was actually 19,4g of soil.
Para mi el proceso de secado en forma natural al aire es tan valido como secar en estufa a los 105 °C , que es una temperatura que se usa por convención, y creo que a esa temperatura haya cabios en la estructura o composición de las arcillas ingresa al campo de las suposiciones, lo cual no es valido. Él tipo de textura si es muy importante porque no es lo mismo secar un suelo arenoso y uno arcilloso, otro factor de importancia es la humedad relativa que pueda hacer que la muestra capte humedad del ambiente, para ello se puede hacer enfriar la muestra dentro de una campana de vidrio con silica gel y asunto resuelto
As said by Michal Stepien, the soil can be dried under the room temperature before estimating soil texture. The moisture content of the weighed soil may be determined, if the moisture of the soil and soil separates vary significantly. Otherwise don't worry about moisture. If at all needed, the moisture content may be subtracted from the individual soil separate (sand, silt and clay) content before doing texture identification by textural triangle.
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