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BOARD OF AGRICULTURE. [Pub. Doc. 



That is to say, an application of 2,000 pounds of barnyard 

 manure brings into the soil practically only 12 pounds of 

 nitrogen, 13.40 of potash and 6.3 phosphoric acid, — very 

 small amounts. An average cropping is found to remove 

 from one acre of land, in one year, 50.5 pounds nitrogen, 

 41.6 pounds potash, 19.1 pounds phosphoric acid. 



To return these amounts to the land would require 8,333 

 pounds of barnyard manure for the nitrogen, 6,332 pounds 

 of barnyard manure for the potash, 6,064 pounds of barnyard 

 manure for the phosphoric acid. 



These figures show that barnyard manure contains too 

 little nitrogen in proportion to its potash and phosphoric 

 acid, and this has been proven over and over again. Of all 

 plant food, the soil lacks and needs most nitrogen. 



As to the proportion of potash and phosphoric acid, they 

 are shown by the last two weights given to be replaced in 

 the soil by nearly the same weight of barnyard manure. 

 This might suit in some soils, but in very many it would 

 not. In England they find this proportional amount of 

 phosphoric acid too little, while in Massachusetts the pro- 

 portion of potash is too little. 



Barnyard manure excels, therefore : — 



1. Because it brings into the land a large amount of the 

 much-needed humus. 



2. Because it contains some of every kind of plant food. 

 Nothing can take the place of barnyard manure. 



It is dejicient : — 



1. In all the three costly elements of plant food. 



2. Especially in nitrogen. 



3. For Massachusetts, in potash. 



It must therefore be re-enforced by all three elements, 

 especially by nitrogen and potash. 



