During the mixing process, it was found to be important to add the water prior to adding the fibres, to prevent floating of the fibres.

even mixing is the most important aspect

uniform distribution of fiber within soil is a matter of concern when you are mixing them together. Development of electrostatic charges on fibers and soil grains during mixing (rubbing) causes problems in getting the uniform distribution. So you should prevent the charge development by adding some water or do the mixing somehow the developing charges can be easily neutralized (discharging). 

Check it out for glance idea of precautions to be taken while mixing fibres.

Regards,

ensure uniform distribution of fibers.

Rotating mixer may be used to check uniform density of mix.

Haider Al-Ani sir, it is a black cotton soil