66 FARMERS' INSTITUTES. 



plant has been composed of parts or elements, which are respectively called 

 the organic or inorganic parts of the plant. That which burned away was 

 the organic part, and that which remained — the ashes — the inorganic part. 

 Chemistry teaches us that these parts are composed of cei'tain elements, 

 fourteen in number, and that these same elements exist in animal and vege- 

 table life. The organized part of the plant consists of four gases, ox3'gen, 

 nitrogen, carbon and hydrogen; the inorganic part, of potash, soda, lime, 

 magnesia, oxides of iron and manganese, chlorine, phosphoric acid, sul- 

 phuric acid and silica. Xow, this is the starting point. Experiment shows 

 that plant life, for its development, must always find and set in motion 

 these elements, but that it combines them in an infinity of proportions and 

 in a variety of structures. The gaseous or organic part is found to be nine 

 times the weight of the inorganic part, or the ash. Now, the organic part is 

 composed of carbon, oxygen, hydrogen and nitrogen, all of which, if we 

 except the latter, are received by the plant from the atmosphere, and the 

 remaining one-tenth, or organic, part of its supjiort is received from the soil ; 

 BO that in reality all the fertility that can be restored to the soil by hand of 

 man is but insignificant compared with what is supplied from the great 

 storehouse of nature — the atmosphere; yet, insignificant as this inorganic 

 element is, it is absolutely necessary to the life and growth of a plant, so 

 much so that if any of it be absent (any of the ten elements, potash, lime, 

 etc.), the plant cannot be produced to perfection. !Xow, the absence of any 

 of these, or any undue portion of one or the other, would make a barren soil, 

 and hence a soil may be rich in one element and poor in another, and conse- 

 quently a soil may be only partially poor. It will be found that our worn- 

 out lands in Michigan are so by continual cropping with some particular 

 class of plants, such as wheat, oats and timothy hay, and these lands are 

 only poor in the elements which 'these take more largely from the soil than 

 any other, that is phosphoric acid and potash. I by no means say that this 

 is all that is wanting, bui these are the principal elements. It will always 

 be found that the relative productiveness of different soils is intimately con- 

 nected either with an abundance or a deficiency of phosphoric acid and pot- 

 ash. Eoot crops especially have ashes rich in potash, and the failure of 

 roots on lands which formerly produced good crops, I^ can safely say, is due 

 to the exhaustion of available alkalies. But supplying one element does not 

 necessarily make the soil grow good crops. In a great number of cases an 

 analysis of soil would be of great service. It is an easy matter to restore fer- 

 tility if Ave know what elements of plant growth are absent or lacking in 

 availability, and what manure contains these elements in the cheapest and 

 most available form. I do not know whether our farmers would or could 

 conveniently analyze their soil, but certainly it would pay. I have known 

 an endless amount of money spent on salt, lime, and other manures, without 

 any benefit, simply because the soil did not require these ingredients. The 

 general cause of the sterility of soils is either the absence of certain constitu- 

 ents indispensable for the growth of jDlants, or the presence of others which 

 exert an injurious or poisonous action; and hence an analysis is often neces- 

 sary in order to find out what injurious element preponderates, and what to 

 apply in order to neutralize it. On the supposition, then, that we know 

 exactly what food our soil is lacking in, how shall we best restore it? And 

 this gets us right into the midst of the controversy on fertility and nitrogen 

 — whether the latter is supplied by the atmosphere totally or partially, or 



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