1:1 soil to water extractions are generally prepared on a volume basis. An equall weight of dried soil and de-ionized water are mixed.
The solution is allowed to equilibrate for 4 hours.
It is then extracted using an air press through qualitative filter paper.
The extract is then analyzed.
Some positive aspects of a 1:1, are the relatively small amount of time and man power involved in acquiring the extract. Also it is a very quantitative reproduce-able method of soil salinity evaluation.
Some negative aspects are that it is not a simulation of potentially realistic environmental conditions as is a saturated paste. Therefore, 1:1 results must be adjusted in order to reflect an accurate picture of the salt concentrations in soil. This adjustment is a point of argument for some in academia.