LIMK, GVPSUM AND GRHEN MANURKS I07 



Mechanical Action of Lime. — On a heavy clay soil lime loosens 

 the soil and makes it lighter and more porous. It relieves some- 

 what the tendency of these soils to puddle. It renders them easier 

 to work and lessens the stickiness or adhesiveness a great deal. 

 We learned that puddling is due to the fine state of division of the 

 particles in clay soils. Lime tends to cause a coagulation or floccu- 

 lation of these fine soil particles. This action is easily demon- 

 strated by placing some clay soil in a glass of water and adding a 

 pinch of lime. When the lime is added and the contents of the 

 glass well stirred, the soil particles precipitate and settle to the 

 bottom of the glass leaving a clear solution of water. 



Lime lessens the tendency of clay soils from cracking because 

 it does not shrink in dry weather. For this reason the addition 

 of lime to clay soils makes them easier to work. On sandy soils 

 lime has an entirely opposite eflfect than on clay soils. Instead of 

 making the soil lighter and more open it binds together the soil 

 particles. It increases the capillary power of light soils and thus 

 m.akes these soils better able to stand dry weather. 



Lime does not add any nitrogen, phosphoric acid or potash to 

 the soil but sets these constituents free. Therefore the continual 

 use of lime will make a soil less productive, hence the saying, 

 "Liming makes the father rich and the son poor." 



Lime Decreases Many Fungus Diseases. — Many fungi and moulds 

 that prosper in an acid soil are destroyed when lime is added and 

 the soil kept alkaline or sweet. Certain rusts, smuts, club root, 

 etc., are due to fungi that require a sour soil for their develop- 

 ment. Lime seems to favor the potato scab fungus and potatoes 

 grown on limed soils usually produce scabby tubers. This fungus 

 may be checked in alkaline soils by dipping the seed potatoes in 

 a solution of formalin or corrosive sublimate before planting.* 



Gas lime is the refuse lime from the manufacture of coal gas. 

 Coal gas is passed over fresh slaked lime which absorbs the im- 

 purities, principally sulphur compounds and gases, from the coal 

 gas. The presence of sulphur compounds in this product makes 

 it unsafe to use because it has a poisonous effect on young plant 

 growth. It may be applied to the soil provided it is allowed to 



