PRACTICE IX 



DETERMINATION OF ACIDITY (OR LIMESTONE REQUIRED) 



OF SOILS 



Place 100 g. of soil in a 400-cc. (or 12-oz.) wide-mouthed bottle, 

 add 250 cc. normal potassium nitrate solution, stopper, and shake 

 continuously for three hours in a shaking machine, or every five 

 minutes by hand. Let stand over night. Draw off 125 cc. of the clear 

 supernatant liquid, boil ten minutes to expel carbon dioxid, cool, and 

 titrate with the standard sodium hydroxid, using phenolphthalein 

 as indicator. 



Surface Subsoil 



(1) Titrations cc. NaOH 



(2) Titrations cc. NaOH 



Av. cc. NaOH 







Percent CaCO 3 required 



What crops, and in what way, does ground limestone mainly 

 benefit ? 



18 



