218 THE PRINCIPLES OF SOIL MANAGEMENT 



The proportionate increase in the water capacity 

 of the sand and decrease of the clay loam is here well 

 shown, and doubtless, if the column had been longer, 

 the compact sand would have had a greater absolute 



capacity than when 

 loose. 



Deep plowing is 

 greatly to be re- 

 commended as a 

 practice to increase 

 the moisture capa- 

 city of the soil, 



Fio. 69. subsoiier that loosens the subsoil by particularly where 

 raising and breaking it. organic matter is 



well supplied. It creates a deep soil, and should estab- 

 lish the best conditions for the storage of moisture, as 

 well as food for the plant. If organic matter is not 

 supplied, deep plowing is not advisable on light sandy 

 soil; but on clay soil it is beneficial because of the 

 loosening or granulating effect. 



The practice of subsoiling aims to locjsen up the struc- 

 ture of the deep subsoil without turning the material 

 to the surface. It increases the ease of root penetration, 

 the rate and depth of percolation, and on clay soil it 

 increases the water capacity. Subsoiling is unnecessary 

 and may even be injurious on sandy soil, and on clay 

 soils must be used with discretion. It is difficult to 

 secure the proper moisture condition of clay subsoils 

 for plowing in the spring in time for spring planting. 

 The soil may be in good working condition, or even dry, 

 while the subsoil is wet enough to puddle. On the other 



