232 APPENDIX 



EXPERIMENT 9 



Effect of Evaporation on Soil Temperature 



1. Fill to within a quarter inch of the top, three 1 -quart 

 granite-ware pans (or any three vessels of equal size and 

 shape), with any soil of the same kind, preferably a sandy 

 loam for this experiment. 



2. With wax pencil or otherwise mark the pans 1, 2, 

 and 3. 



3. Place a small piece of filter paper upon the surface 

 of the soil in pans 2 and 3. 



4. Upon the filter paper in pan 2, pour an amount of 

 water equal to 20 per cent of the weight of the soil in the 

 pan. 



5. Upon the filter paper in pan 3, pour water until the 

 soil is slightly more than saturated. 



6. Place a cover on each of the three pans and set the 

 pans together, either in the laboratory or out-of-doors, 

 where the temperature will remain fairly constant, and 

 permit to stand till the following morning. 



7. Remove covers and determine the temperature of 

 the soil in each pan by inserting a thermometer bulb 

 just below the surface, and record temperature in each 

 case. It is desirable to have a thermometer for each pan 

 and to allow it to remain in position during the period of 

 the experiment. 



8. At the end of each hour, for three to six hours if 

 possible, again determine the temperature of the soil in 

 the same manner and record temperature. 



9. Plot curves of temperature for the three pans. 



