INSTITUTE PAPERS. 



SOIL FERTILITY. 

 By Prof. Fred W. Card, Sylvania, Pa. 



The fertility of the soil is represented by four fundamental 

 factors, — texture, moisture, plant-food, and living organisms. 

 By soil texture we mean its physical condition, whether mellow 

 and friable, soft and sticky, or hard and lumpy. Texture is 

 important for the following reasons : First, the moisture capac- 

 ity is increased ; second, the air capacity is increased ; third, 

 it aids in rendering available plant-food already in the soil; 

 fourth, it lessens extremes of temperature; fifth, it affords bet- 

 ter conditions for root growth. 



Good texture may be maintained in a fertile soil or restored 

 when lost, by the following methods : First, underdraining. 

 This is applicable only to wet, undrained soils, or those with 

 a heavy subsoil. The first object of underdraining is to remove 

 surplus water, thereby rendering it possible to work the soil 

 earlier in the spring and sooner after rains. A secondary effect 

 is to make the soil warmer. The evaporation of water con- 

 sumes much heat. When hundreds of barrels of water lie on 

 a low field to be evaporated by the sun's rays, its heat is entirely 

 absorbed in doing this work; consequently a wet soil is well 

 termed a cold soil. Underdraining also increases the feeding 

 ground for roots. A water-logged soil, or one in which the 

 water-table stands near the surface, induces surface rooting of 

 the plants growing upon it, as roots will not readily enter a com- 

 pact, wet soil. Removing this surplus water enables them to 

 run deeper. Underdraining also enables land to withstand 

 drought better, largely for the reason just cited. Roots in an 

 undrained soil, running near the surface, are in a position 



