MANUKES AND THEIR APPLICATION. 311 



decay, and lime is, therefore, an excellent thing to apply to old 

 fogged-up pastures and moory or peaty land overcharged with 

 organic matter. 



But there are other acids produced in the soil. I have already 

 told you that there are myriads of germs in the soil converting 

 the nitrogen of organic matter into nitric acid. Lime seizes hold 

 of the nitric acid thus formed, converting it into nitrate of lime, 

 and thus clears the way for the production of more nitric acid, 

 and still further hastens the process of decay. Not only so, but 

 when nitrate of soda is added to a soil containing lime salts, a 

 chemical action takes place between these, and nitrate of lime 

 is formed. iSTitrate of lime is a verv soluble salt, and durincf 

 wet weather it soon finds its way down through the soil and 

 subsoil and escapes into the drains. That is the reason why 

 nitrate of soda is so transitory in its effect. 



It is unfortunate that one of the results of liming should be 

 to hasten the loss of nitric acid, and it is important that we 

 should endeavour to diminish that waste as much as possible. 

 The only way to catch the nitrate in its downward progress is 

 by means of the roots of plants which absorb it into their tissues. 

 It is therefore very beneficial, as Dr. Lawes pointed out some 

 time ago, to have the ground covered with vegetation. Any 

 kind of green growth is better than bare soil, and thus it is that 

 summer fallowing is necessarily a wasteful practice, which is 

 happily going fast out of fashion. 



The thicker the vegetation and the more closely the roots of a 

 crop possess the ground, the less chance is there of a loss of 

 nitrate. There is no crop which is thicker than a grass crop, 

 and you are all familiar with the fact that of all crops on the 

 farm there is none so " grateful " (to use a common expression) 

 for the application of nitrate of soda as a grass crop. 



This, I think, will also explain the unexpected result obtained 

 by Dr. Voelcker in his recent experiments with farmyard manure, 

 that it is more economical and therefore more advantageous to 

 apply farmyard manure to the grass crop than to the root crop 

 as is the usual custom. 



It may be asked why, when lime is apt to carry away the 

 most valuable constituent of the soil, its employment is still 

 recommended. That has been partly answered already, but 

 there are other reasons, one of which is that there are other acids 

 in the soil, whose presence is not so desirable as nitric acid, 

 such as muriatic acid and sulphuric acid, not to mention several 

 organic acids. In a very instructive paper recently published 

 by Professor Mayer, he has given the results of some experi- 

 ments with kainit and other salts, consisting mostly of sulphate 

 and muriate of potash, carried out with the view of discovering 

 the cause of the frequent failure of these forms of manure. His 



