78 



SOIL AND ITS RELATION TO ROOTS 



Observations. — Tabulate the exact amount of water left in 

 the soil in each case. 



Conclusion. — 1. Of what use is the forest covering of leaf 

 mold ? 



2. Which kinds of soils would be most favorable for crops and 

 why? 



Problem 60 : What do plants take out of the soil ? 



Materials. — Glass jars, distilled water, nutrient solution, corn 

 seedlings. 



Method. — Partly fill five jars, the first with distilled water, 

 the second with nutrient solution ^ without potassium nitrate, a 

 third with nutrient solution without calcium phosphate, the 

 fourth with nutrient solution without ferric chloride, and a fifth 

 with nutrient solution. Place in the jars corn seedlings with their 

 roots in the liquids. Keep them under observation for two or 

 more weeks. 



^ A nutrient solution known as Sach's solution may be made as follows : 



Potassium Nitrate 1.00 gram 



Sodium Chloride 0.50 gram 



Calcium Sulphate 0.50 gram 



Magnesium Sulphate 0.50 gram 



Calcium Phosphate 0.50 gram 



Ferric Chloride 0.005 gram 



Distilled Water 1000.00 grams 



Add the ferric chloride at the time the solution is to be used, by adding a drop or 

 so to the solution in the bottle used for the seedlings. 



