Not on texture. Texture is defined as the relative fraction of the three soil particle sizes: sand, silt and clay. Drying the sample will not make the particles any bigger or smaller.  Actually the most precise method for determining particle fraction, siebing, has to be carried out with dried samples.

Oven drying the soil sample will affect the soil texture if you use the feel method since oven drying may affect the organic matter content which affects the texture by the feel method. However, if you are using either the pipette or hydrometer method the effect would be negligible.

Soil texture it is not influenced by drying the samples. 

Dear Binay:

You can use oven dried soil samples. To my knowledge, the point is not relevant as you surely will use the pipete method for clay fractions.

Cheers Humberto

You can use only dried soil samples for determination of soil texture by touch and feel method (initial step), sedimentation method (pipette method ) and hydrometer method.  Except touch and feel method, the other two methods are based on quantification principle. If you know the exact weight of the sample, the initial dry weight of the sample  (air dried or oven dried), then only you can get the exact value of sand, silt and clay. If you use the air dried soil sample then you must use moisture correction factor for that. Hope its clear. All the best.

Air dried samples are alright for the determination of texture, oven drying to constant weight at 100-105 OC is not essential as this may effect the textural separates. As Dr. J. Dinakaran has elaborated, the important point is to know the exact weight of sun dried soil used for analysis. In areas or season when soil moisture is high and air temperature is low, then moisture correction factor seems necessary if the issue is under investigation. However, for farmer advisory purpose air dried samples could be and no moisture correction factor will be necessary.

Relative size of the soil particles is called soil texture. In the process of soil texture analysis by International Pipette Method  temp. is not very important. Though soil analysis is done by drying samples at room temp.

You should follow the standard method. I wonder what makes you think to use heated soil samples for textural class analysis.

I do agree with the above comments given by different soil scientist, drying sample in oven i think just time consuming

Binay ji,

Dilpikumar sir said rightly. You have to use air dried samples for texture determination.  In my view, on heating soil samples in oven, there will be quick contraction of clays which may make adhesion/cohesion between soil to moisture and clay to clay there by strong bonding may happen. During separation, they may act as large particles. And you may get less values for clay content. Hence do not use oven dried samples for soil analysis of any parameter except soil . moisture.

The way or temperature of drying is without influence on the particle size results, but take care you have properly destroyed any organic matter and calcareous compounds.

Yes oven drying soil at high temperature could induce errors in the final results but may not change the textural class.

Yes, oven-dried samples should be used for soil texture determination.  70°C is more than hot enough for the initial drying stage that precedes sieving.  A subsequent 105°C drying stage is required before weighing to determine soil texture.  Oven-drying samples will not have an effect on soil texture.  Inadequate drying, however, can skew one's texture data toward smaller particle sizes, as clay holds water more strongly than silt, which holds water more strongly than sand.

Below is a link to Cornell University's Soil Health Laboratory's manual.  On page 35 is a concise description of the Kettler et al. 2001 soil texture method.  This method is simple, works well, and I have used it hundreds of times.

• Link to method description: http://soilhealth.cals.cornell.edu/training-manual/
• Source method:  Kettler, T. A., J. W. Doran, and T. L. Gilbert. 2001. Simplified method for soil particle-size determination to accompany soil-quality analyses. Soil Science Society of America Journal 65:849–852. 

http://soilhealth.cals.cornell.edu/training-manual/