The Problem of Impoverished Lands. 107 



competition in trade if liandicapped as Mr. Black is. When the respec- 

 tive farms were reclaimed from ,the forest, they were considered to 

 be alike in character of soil, and the rain falls impartially on each. 



AYhy the difference in cost of production between Black and 

 White ? There are many points of difference in their methods, but 

 we are free to say that one of the essential differences is in tillage. 



14. The plant needs water. — When Mr. White contemplates a 

 crop of potatoes, he proceeds to make an estimate of what the crop 

 will require and how he can provide for tliat demand. Perhaps the 

 greatest of all needs is water. By turning to Cornell Experiment 

 Station Bulletin 120, page 419, it will be seen that in a dry season a 

 bushel of potatoes requires about three tons of water for its produc- 

 tion. If Mr. White expects 200 bushels of potatoes per acre, he 

 must somehow manage to provide 600 tons of water for each acre. 

 He has no facilities for irrigation, and his only resource is to make 

 the soil a reservoir. He must store the supply left by winter snows 

 and spring rains, and also the irregular rainfall that comes during the 

 season's growth. ♦ Speaking in broad averages, in soils most commonly 

 met with, this storage possibility amounts to about 300 tons of water 

 per acre in the iirst eight inches of the soil. It must be understood 

 that this amount is not in the form of standing water, for water stand- 

 ing in the soil for any length of time injures both soil and plant. 



15. The most useful form of water for jjlants is film vwisture. — 

 Water is capable of assuming many forms, sucli as steam, vapor, ice, or 

 free-moving liquid. The condition most valuable in the soil is none of 

 these, but is in the form of film moisture. This film moisture can be 

 shown by dipping a marble into water and observing the film of water 

 surrounding it on all sides. When each soil-grain is covered with film 

 moisture, as the marble is, the ideal conditions of soil moisture exist. 

 This form of water is largely independent of gravitation and travels 

 readily in all directions, as can be seen by dij^ping a cube of sugar into 

 a spoonful of coffee. It is capable of transporting plant-food to the 

 roots of plants from remote corners, where the roots do not reach. 



It will be observed that film moisture is held only on the surface 

 of soil-grains. The more the soil is pulverized, the more soil-grains 

 there will be, and therefore the greater amount of surface to hold 

 film moisture. 



