Tilth and Tillage of the Soil 1763 



pry their way into small crevices, and cut the soil in every direction. 

 Crops having fine, fibrous roots, such as buckwheat, are especially noted 

 for their beneficial effect on heavy soil. It is generally recognized that 

 after a clay soil has developed a poor condition by a period of unwise 

 cultivation, good tilth can best be obtained by laying down to grass for 

 a period of years, after which the earth turns up friable and mealy. (Fig. 

 88.) 



The roots of plants, the earthworm, and other soil life, operate only 

 in moist and well-ventilated soil, as has already been noted. If we would 

 have their cooperation, the land must be well drained. The mat of vegeta- 

 tion on the surface formed by plants, especially grasses, protects the 

 soil from the beating and puddling action of rain, from melting snow, and 

 from washing. Plants used for this purpose are known as cover-crops. 



TILLAGE 



Principles of tillage 



Tillage is the manipulation of the soil by means of implements. It 

 may have many objects. The soil may be plowed in order to turn under 

 stubble, manure, and rubbish. It may be cultivated deeply and thrown 

 into ridges for the purpose of drainage. It may be stirred shallow in 

 order to dry out the soil and to create a mulch. One cardinal object of 

 tillage is to stir the soil and expose it to air and light for their sanitary 

 effect. 



Lumpy soils need to be pulverized, sandy soils to be packed. Some- 

 times, in planting small seeds, soil is compacted in order to increase 

 its capillary capacity and to draw moisture to the surface from the subsoil 

 as an aid to germination. Whatever the ultimate result of the tillage 

 operation, all operations affect the soil in one of two ways: either they 

 loosen the soil and render it more open and friable, or they pulverize 

 and compact it and make the structure denser. Choice of the proper 

 tool must be guided by the purpose for which it is to be used. If the 

 soil is to be turned over and the rubbish covered, a moldboard plow should 

 be chosen. If the operation is to reach deep into the soil a larger tool 

 will be required. In order to stir the subsoil a subsoil plow may be neces- 

 sary. In order to create a mulch on a sandy loam soil we may select 

 the weeder — a light tool which very thoroughly stirs the soil to* the 

 depth of an inch. On lumpy or stony soil a spring-tooth harrow or a 

 large-toothed cultivator may be necessary. In order to compact the soil 

 some form of roller may be used. The kind of change to be effected in 

 the soil should first be determined, then the tool may be chosen which 

 will best accomplish the purpose. 



