Soil texture The number on the hydrometer that is visible (above the soil solution) is recorded. A blank (containing only water and the dispersing agent) is used to calibrate the hydrometer. The values recorded from the readings are used to calculate the percent clay, silt and sand. The blank is subtracted from each of the three readings. The calculations are as follows: Percent silt = ( dried mass of soil - (sand hydrometer reading - blank reading) / (dried mass of soil) *100 Percent clay = (clay hydrometer reading - blank reading) / (dried mass of soil) *100 Percent sand = 100
Granular convection slipped below them. Repeated freeze-thaw cycles in a single year speeds up the process. This phenomenon is one of the causes of inverse grading which can be observed in many situations including soil liquefaction during earthquakes or mudslides. Granular convection is also exemplified by debris flow, which is a fast moving, liquefied landslide of unconsolidated, saturated debris that looks like flowing concrete. These flows can carry material ranging in size from clay to boulders, including woody debris such as logs and tree stumps. Flows can be triggered by intense rainfall, glacial melt, or a combination of the two. Granular convection