to 

 Study 



the soil which cannot positively answer, full though it is of 

 life, to the living crop which can; so today we feed the crop ^^**^ 

 rather than the soil. In the modern sense, therefore, the farmer ^^^ ^^^ ' 

 is a manufacturer and the soil is his machine, into which he soil 

 puts plant food and out of which, by the aid of nature, includ- 

 ing the bacteria and other seen and unseen forces, combined 

 with his own efforts, he takes his product at harvest time. If 

 the soil machine is a good one — that is, of the right texture and 

 retentive of plant food, full of active nitrifying bacteria or 

 ''yeast" — so much the better. If it has a balance of crop-pro- 

 ducing power to its credit, we seek to preserve that balance 

 for an emergency, as the prudent man preserves a balance in 

 the bank in case of need. 



In stock feeding we chiefly concern ourselves with a study 

 of the animal and its needs. So in plant feeding we must What 

 make an intelligent study of the needs of the living crop, and 

 in the study of this problem we must also study the soil, its 

 latent or potential fertility, its physical and chemical charac- 

 teristics, and particularly the lower orders of life which it con- 

 tains, the bacteria and other unseen forces, to the end that we 

 may know what each contributes to the upbuilding not alone 

 of the soil, but of the crop life above the soil, upon which all 

 higher forms of life and activity depend. 



Our problem then is not only to conserve, but to supply the 

 balance of ready plant food required by the growing crop, as 

 milk or prepared food is supplied to the growing child. 



What Plants Need 



Without going into an elaborate analysis of plants, let us 

 come immediately to consider their chief needs and the chief 

 deficiencies of all soils that have been farmed for some time. To 

 ascertain what plants need, we must first know what they are 

 composed of. Professor Brooks aptly illustrates the matter in this 

 way: 100 lbs. of green grass, thoroughly dried in the sun, will 

 shrink to about 25 lbs., the loss of 75 lbs. being water. If the 

 25 lbs. is put in an oven and heated to 212° (boiling point of water), 

 we can drive off from 12 to 14 lbs. more, or from 86 to 88 lbs. of 

 water in all. The perfectly dry, remaining portion is called 

 by the chemist '* organic matter." If these 12 or 14 lbs. 

 of organic matter are burned, there will be left from 1 to 3 lbs. of 



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