FERTILIZING 105 



(3) It tends to preserve nitrogen. (4) It flocculates heavy soils. 

 (5) It has some fungicidal and insecticidal value. It is often effec- 

 tive against snails. (6) It corrects the toxic action of magnesium 

 and also of many other bases when they become present in 

 injurious amounts. 



This sixth function of lime may frequently be an important one, 

 and opens up a question that has not received the attention it de- 

 serves in connection with crop fertilization in general. This question 



Fig. 46. Manure versus nothing 



Row on left, receiving stable manure, third year, produced 373.S bushels per acre. Row on 

 right, receiving nothing, produced 27.9 bushels per acre. Variety, York Imperial. (After 

 Pennsylvania State College) 



is that of the toxicity of the salts of various bases, especially those 

 of the heavy metals, when present alone in solution or when dis- 

 tinctly predominating in solutions otherwise weak. Related to this 

 is the fact that the observed toxicity of these salts may often be 

 reduced or entirely neutralized by the addition of other bases. This 

 was first discovered in connection with magnesium and calcium 

 about 1883, but it has since been found true of salts of various 

 bases or metals, such as sodium, potassium, strontium, barium, iron, 

 manganese, nickel, cobalt, silver, mercury and the NH 4 radical in 

 ammonium compounds. The toxic action of these salts has been 



