LIMING THE SOIL. 55 



tons of pulverized limestone, and it acts quickly and is almost 

 immediately effective. 



Too Much Lime. 



There should be just lime enough to be constructive in its 

 effect. 



Too much lime is destructive instead of constructive and 

 enriching. 



Too much lime will liberate more plant food than the plant 

 can assimilate, because the combustion of organic matter is too- 

 rapid. 



Too much liberation of plant food results in exhausting the 

 soil. 



When more plant food is available than can be used it will 

 leach out. 



Brief Summary. 



The forces that lime exerts on the soil may be summed up 

 as : chemical, physical and biological. 



1. Chemical action 



(a) Changing insoluble potash compounds into available plant 

 food. 



(b) Neutralizing acids. 



2. Physical action 



(a) It causes baked soils to become granulated, pulverized or 

 flocculated. 



(b) It binds together the loose particles in sandy soils. 



3. Biological action 



(a) It renders the condition of the soil favorable for the de- 

 velopment of bacteria. 



Lime sweetens the soil. 



Lime hastens the decay of organic matter in the soil. 



Heavy clay soils require about twice as much lime as sandy- 

 soils. 



To make lime effective it should be spread on the surface 

 and harrowed into the soil thoroughly. 



It should not be exposed on the surface over night or during 

 a storm. 



