44 Elementary Principles of Agriculture 



dition, of the soil in either case would have less water- 

 storage space, and be less liable to set free liberal supplies 

 of plant food. Some soils are so porous and loose that 

 the moisture drains away, and the air circulates so freely 

 that they dry out too rapidly. 



71. Capillary Attraction is that force which causes 

 water to rise in tubes or between particles of solid 

 substances. The narrower the tube the higher will the 

 liquid rise against the force of gravity. Fine-grained 

 soils having smaller pores or spaces between their par- 

 ticles than coarse-grained soils, will lift water from 

 below nearer to the surface than will coarse-grained 

 soils. They will also hold more moisture in satura- 

 tion than coarse soils, hence, are generally the bet- 

 ter. Therefore, thorough tillage of the soil is bene- 

 ficial. 



72. The Problem in Soil Management is to bring the 

 soil to an ideal condition for the healthy growth of the 

 roots. Some soils must have the particles made finer, 

 and some must be made coarser by causing the finer 

 particles to combine. 



73. How to Improve the Texture. Good texture is 

 important and dependent on the size of the soil par- 

 ticles. In soil treatment the object, then, is to find the 

 best means of modifying the size of the particles until 

 the soil is mellow and friable. There are three general 

 ways of changing the texture of the soil' 



(a) By applying mechanical force, as in the opera- 

 tions of spading, plowing, harrowing, etc. This acts 

 directly to make the particles finer. If heavy clays 

 or black waxy land are tilled while wet, the particles 

 are forced closer together, and we say the soil is " pud- 

 dled." This is a brickmaker's term. In making brick, 



