THE YEAST OF THE SOIL. 21 



Is this not applying plant food in homoeopathic doses ? And yet , 

 1,000 lbs. to the acre of concentrated fertilizer, such as I have de- 

 scribed, is an average dressing for many crops. When one witnesses 

 the rapid growth of the corn crop, and thinks of the infinitesimal 

 quantity of applied nourishment allotted to each stalk — so little 

 to produce so much — it seems like a miracle of nature, even more 

 wonderful than the miracles of Scripture. 



Stable Manure and Commercial Fertilizers. 



It is estimated that a cord of stable manure, weighing 4,000 lbs., 

 contains on the average 50 lbs. of plant food, worth about $3, the 

 remainder (3,950 lbs.) being water, straw", and organic matter. For 

 the 50 lbs. of plant food to be rendered available, we are dependent 

 very largely upon bacterial action in the manure and in the soil. 

 In the old days, as I have said, we composted manure in advance in 

 order to hasten the process of decomposition and increase its availa- 

 bility. Now, as a rule, depending upon commercial manures for 

 active available plant food, we apply the manure on the soil directly 

 as we produce it or receive it. 



While there are only 50 lbs. of actual plant food (nitrogen, phos- 

 phoric acid, and potash) in a cord of manure, yet we must not over- 

 look the value of the organic matter, straw, etc., not only for the 

 humus which is added to the soil by means of the manure, but also 

 for the improved physical condition which it imparts to the soil. 

 This humus, no commercial manure supplies, and in this respect 

 stable manure is superior to commercial manures, but the value of 

 this excessive amount of humus in stable manure, as a source of 

 plant food, depends, as we have seen, not only upon a thorough dis- 

 tribution of the manure in the soil, but chiefly on normal conditions 

 of warmth and moisture, in order that bacterial action may be in- 

 duced and by means of which it is rendered available. Thus, when 

 we solely rely on stable manure, we are more dependent on weather 

 conditions than when we apply predigested fertilizers, or part ferti- 

 lizer and part manure. 



Stable manure, as a by-product of the farm, or where it can be 

 bought and hauled at a price that is not in excess of its intrinsic 



