SATURATIOX OF THE SOIL. 73 



nitrate of soda leaches A^ery readily indeed. We can only 

 sa}' that about it. INIoreover, we can say that every particle 

 of nitrogen which runs through the soil, agriculturally speak- 

 ing, passes through as nitric acid: the plant feeds upon 

 nitric acid, and not upon ammonia, and it is only through a 

 series of changes that we get plant-food to our plants. 



1 may also say what was stated by Liebig in 1842 (the 

 date, I'think, of his first edition), which has been overlooked 

 largely in our discussions, and yet it is one of the most 

 important statements ever made concerning rational agri- 

 culture ; and that is, that it is not so much the amount of 

 fertilizing elements in the soil which concerns us as farm- 

 ers as it is the condition of saturation of the soil. To illus- 

 trate this statement: If I had a box of earth, and on the 

 top of this box I placed super-phosphate, containing soluble 

 phosphoric acid, and then poured water upon that, and then 

 allowed the water to leach and pass out below, you would 

 find that the water which was still put on would carry this 

 phosphoric acid down into the soil until that phosphoric acid 

 (and here is the point) was evenly diffused, so that every 

 single particle of soil held the same quantity of phosphoric 

 acid, just as far as that wat(jr could pass down ; and, when 

 that took place, then the extra water poured on would sim- 

 ply pass through as water, taking out none of the fertilizing 

 elements. If, having your phosphoric acid evenly diffused 

 and distributed through the soil, you apply more phosphoric 

 acid and more water, your phosphoric acid passes down an 

 additional depth in that soil ; and, agriculturally speaking, it 

 is this saturation of the soil which concerns us more than 

 the quantity of manure. So that, although we may have 

 the material for five hundred crops in our soil, yet it may 

 happen that we cannot get, agriculturally, a crop from that 

 soil ; and yet the addition of only enough material for one, 

 two, or three crops, may give us large crops. Just that 

 little addition which adds enouG^h to the immense sources of 

 fertility in the soil to bring those sources up to the point of 

 saturation will make all the difference between no crop and 

 a large crop. Does not that meet your views. Dr. Nichols ? 



Dr. Nichols. Yes, sir. 



Mr. Whitaker. Would not the character of the soil 

 make some difference? 



10 



