Ortide. 

 Date. . 



(40) 



EXERCISE 14 



• Capillary Moisture 



Purpose. — The determination of capillary moisture in samples of field soil. 



Capillary mmsture is that water which is held in the soil by surface tension 

 of the soil particles. If soil is exposed to the air it can be entirely evapo- 

 rated at room temperature, 



PLAN 



1. Take four pint jars with tight-fitting tops. Secure, either from the field 



or greenhouse, according to directions from the instructor, moist samples 

 of the following soils : sand, sandy loam, clay, and muck. Bring to the 

 classroom and, using the square soil pans, determine the moisture content 

 of the soil, as follows: 



2. Label with a wax pencil and weigh on the balances the empty pan. Then 



immediatel}^ weigh into it 100 grams of the moist soil as quickly as 

 possible. 



3. Do the same with the other soils. 



4. Set the pans away carefully and weigh every few days until a nearly 



constant weight is reached. 



5. At the completion of the experiment carefully preserve these soils and 



determine the amount of hygroscopic moisture in them according to 

 directions as given in the following experiment. 

 The amount of capillary moisture which has disappeared into the air is indi- 

 cated by the loss in weight. Calculate the percentage of capillary water, 

 using the dry soil for the base. 



Capillary Moisture 



