vi.] ACTION OF CAUSTIC LIME. 57 



nitrate of potash, and the quantity is largely increased 

 by small additions of liquid manure. These conditions 

 are very commonly fulfilled in the soil, and we may 

 therefore fairly consider that lime acting upon the farm- 

 yard manure, and the inorganic matter of the soil 

 promotes the production of nitrate of potash. 



1 08. We have already noticed the necessity which 

 exists for a supply of lime to meet the requirements 

 of the crops so far as regards that quantity which the 

 plant receives as food. Every cultivated plant 

 needs a supply of lime for the proper building up of 

 its structure, but some, like the beans and peas, clover 

 and root crops, require it in greater abundance than 

 other crops. 



109. The physical or mechanical action of 

 lime upon heavy clay soils is another feature of its 

 character which must not be overlooked. It makes 

 these soils more mellow, and therefore more easily 

 cultivated, at the same time it favours the admission 

 of air and water into the soil, with all their powers for 

 developing its fertility, and it gives a more healthy 

 character to the vegetation growing upon such land. 



no. The advantages arising from the use of caustic 

 or quick-lime may be enumerated as follows : 



(1) It encourages the decomposition of the organic 

 matter in the soil. 



(2) It neutralizes the organic acids which make land 

 sour, and it improves the quality of the herbage. 



(3) It assists the liberation of alkaline matters 

 (potash and soda) from the dormant ingredients in 

 the soil. 



(4) It promotes the formation of the double silicates. 



(5) It favours the production of nitrate of potash. 



(6) It contributes food essential for the perfect 

 growth of the crops. 



(7) It improves the physical character of the soil, 

 and promotes healthy growth. 



These are exceedingly important duties for any 



