INTRODUCTION 



soil is as necessary to the changes producing avail- 

 ability of plant-food as it is to the changes essen- 

 tial to life in the human body. A water-logged 

 soil is a worthless one in respect to the production 

 of most valuable plants. The well-being of soil 

 and plants requires that the level of dead water 

 be a considerable distance below the surface. 



When a soil has recently grown trees, the rot- 

 ting stump roots leave cavities in the subsoil that 

 permit the removal of some surplus water, and 

 the rotted wood and leaves that give distinctive 

 character to new land are absorbents of such water. 

 As land becomes older, losing natural means of 

 drainage and the excellent physical condition due 

 to vegetable matter in it, the need of drainage 

 grows greater. The tramping of horses in the 

 bottoms of furrows made by breaking-plows often 

 makes matters worse. The prompt removal of 

 .excessive moisture by drains, and preferably by 

 underdrains, is essential to profitable farming in 

 the case of most wet lands. The only exception 

 is the land on which may be grown the grasses that 

 thrive fairly well under moist conditions. 



Lime. The stores of lime in the soil are not 

 stable. The tendency of lime in most of the states 

 between the Missouri River and the Atlantic sea- 



[7] 



