Soil moisture content determination (drying method)

1, called sample (>1mm dry soil) about 10 g, placed in a dish of known weight;
2, put in
oven
, at 105-110 oC (high temperature,
organic
-matter easy-to-carbonization loose) temperature baked to constant weight (about 8 hours);
3, remove the
drying
(the desiccant in the dryer calcium chloride or color-changing silicate to be replaced frequently) cooling for about 20 minutes, immediately said Weight;
4, i.e. 2, 3 repeat baking for three hours, remove the dryer, cool, immediately re-weighing (the difference between secondary repetition, not greater than 3 mg);
5, the result calculation:
(1) based on air-dried soil Percentage of moisture (usually used for chemical analysis)
WCF%/(W2-W3)/(W2-W1)×100
(2) Percentage of moisture based on drying soil
WCH%/(W2-W3)/ (W3-W1)×100
: W-water content (%); W1-weighing dish weight (g)
W2-weighing dish and air-dried soil weight (g); W3-weighing dish s-drying soil weight (g)