34 HANDY-BOOK OP HUSBANDRi. 



animal has rejected, in the manure, as to have the largest possible 

 supply for his future crops. 



PHOSPHORIC ACID. 



Phosphoric acid is, in a certain sense, even more important to 

 the farmer than nitrogen. This latter is supplied in limited 

 amount by natural process, — it is absorbed by the soil directly from 

 the atmosphere, and it is brought down in the water of rains. 

 Phosphoric acid, on the contrary, is a fixed ingredient of the soil, 

 and it is never brought to it by wind and rain. We have, in the 

 soil, a certain amount, and only a very small amount, while of this, 

 the larger part is locked up in the interior of pebbles, or compact 

 clods which no root can penetrate. All that is available to a crop 

 is that which, being on the surface of the particles of the soil is 

 directly within the reach of roots, and of such roots as come in 

 contact with those particles. Probably, when any soil has been 

 exhausted by improper husbandry, it is, in ninety-nine cases out 

 of every hundred, the phosphoric acid that is gone. From Maine 

 to Minnesota the gradual advance of " enterprise," — that sort of 

 enterprise which, as it passes from east to west, reduces the 

 yield of wheat from 30 to 12 bushels per acre, — has been marked 

 by the taking up of new lands, by the production of good crops 

 for a few years, and of a precarious subsistence for a few more, 

 and by the destruction of the profitable fertility of the soil within 

 the life-time of the second generation, — all through ignorance or 

 disregard of the value of phosphoric acid, and of the limited 

 ability of the most fertile soils to supply it to consecutive crops. 

 It is commonly urged, when phosphoric acid is mentioned, that 

 most farmers do not know what it is, that a very large majority of 

 them never heard of it. Speak of the use of phosphate of lime, (which 

 is valuable mainly on account of its phosphoric acid,) to a man 

 who is unacquainted with it, and he will probably say that it may 

 be a good manure in "some parts," but that he does not know that 

 it would do any good on his land. If he has just settled on new 

 land at the West, he will show you his deep black loam, that " has 



