The PROF>LE\t OF Impoverished Lands. 100 



Broadly stated, the native plant food amounts to as much as can be 

 bouglii in $2,000 worth of connnercial fertilizers. The liner soil has 

 another advantage in affording a greater area for root pasturage. It 

 is not uncommon for farmers to think of plant- food in the soil as in 

 the condition of salt or sugar which is capable of being immedia- 

 tely dissolved by water and at once appropriated by the plant, or 

 like potash in ashes that can be soaked out. Plant-food exists in this 

 form only to a limited extent. A man might famish if locked in a 

 granary filled with wlieat ; yet a chemist would say that there was 

 enough food near him to feed a hundred men. This illustrates how 

 nature has stored^ much of the plant-food in the soil. It has to go 

 through many changes before it can be appropriated by the plant. 

 The soil is a factory in which the work of preparation is carried on. 



IT. The soil is a Ictboratory. — Some of the agents employed in 

 this factory are film moisure, air and heat ; and if these are not fur- 

 nished in the proper extent and condition, the factory runs in a 

 sluggish way, if it does not stop altogethei-. Good tillage does much 

 to hasten the activities of this factory by allowing free ingress to 

 the soil of film moisture, air and heat. Air is necessary for a sup- 

 ply of oxygen, and heat to facilitate fermentation and other vital 

 processes. 



The importance of air and heat in the soil brings us to the ques- 

 tion of drainage. Air cannot enter a soil freely which is filled with 

 standing water, and growth of micro-organisms is hindered. 



18. Wet soils are cold. — Standing water is a great absorbent of 

 heat. If no provision is made to drain it away, it must be evapo- 

 rated away. Thereby heat is lost. The soil is cold. A great many 

 barrels of water can be standing on an acre of ground and not attract 

 much attention. 



To appreciate the amount of heat necessary to evaporate water, 

 one has only to chop, split and burn beneath a cauldron kettle 

 enough wood to evaporate a barrel of water. Every barrel that is 

 evaporated from the soil by the sun absorbs as much heat as is 

 expended by the wood used under the kettle. The soil and plants 

 are perhaps chilled for want of that heat. This is the reason that a 

 wet soil is said to be cold. 



19. Drained soils resist drought. — Some farmers have the notion 



