178 BOARD OF AGRICULTURE. 



be used ought to contain from thirty to thirty-five pounds of 

 avaihil)le nitrogen, from eleven to twelve pounds of available 

 phosphoric acid, and from forty-five to fifty pounds of 

 soluble potassium oxide, — such fertilizer, made of the best 

 ingredients, would cost from eight to nine dollars. It is not 

 advisable to reduce the nitrogen in our grass manures to too 

 small quantities, for the best grass crops contain the largest 

 amount of valuable nitrogen compounds. 



No single article of plant food acts independently of the 

 rest ; a liberal amount of nitrogen assists in the liberal 

 assimilation of phosphoric acid and potash ; these elements 

 have a close relation to each other 'u\ many of our fodder 

 crops. 



As a phosphoric acid source for grass lands, ground bones 

 may obtain the preference, although all kinds of phosphoric 

 acid-containing materials may be used, provided they furnish 

 in duo time the desirable amount of available acid. 



Our main commercial sources of potash for plant growth 

 are unleached vegetable ashes, as hard- wood ash and of late 

 cotton-seed hull ash, and so called German potash com- 

 pounds. 



Wood ashes are a valuable fertilizer for grass lands if 

 applied in sufficient quantity ; our average unleached Canada 

 wood-ash contains from 5 to 6 per cent, of potassium oxide, 

 1.5 to 2.5 per cent, of phosphoric acid, from 30 to 35 per 

 cent, of calcium oxide (lime), besides small quantities of 

 every other essential mineral element required for a success- 

 ful growth of plants. 



This circumstance imparts to it a special fitness for a 

 general fertilizer. The absence of nitrogen is somewhat 

 compensated for by the presence of a liberal amount of lime, 

 which favors a rapid decomposition of the vegetable matter, 

 contained in the soil. The nitrogen of the vegetable refuse 

 matter becomes thereby in a high degree available. 



The good effects of wood-ash is for this reason more strik- 

 ing upon moist grass lands, rich in vegetable refuse matter 

 than upon dry lands, which as a rule contain less of the 

 latter. 



Dry grass lands benefit usually more by an application of 

 some suitable German potash salt, muriate of potash or 



