Uradc. 

 Date. . 



(38) 



EXERCISE 13 



Total Moisture Determination 

 Purpose. — To determine the total moisture content of field samples of 

 different soils. 



2. 



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, loam, clay, and muck. Bring to the lab- 

 oratory. 



Secure four round evaporating dishes and after numbering determine their 

 weight. Next weigh into each a fifty -gram sample of the soil the moisture 

 content of which is to be determined. 



3. Place the samples in a drying oven the temperature of which is slightly 



above the boiling point of water and allow to remain for twelve hours. 

 Later remove to a dry chamber and allow to cool. Weigh as quickly as 

 possible. Then return to the oven and heat again and reweigh in order 

 to be sure that all moisture has been driven off. 



4. Determine the total moisture by dividing the weight of moisture by 



weight of dry soil. 

 Several samples of soil taken the same day from different fields will enable 



the student to determine the relative water-holding capacity. 

 In making the calculations net weights only must be used. Eliminate the 



weight of dish in each case. 



Total Moisture 



