PRINCIPLES OF PLANTING AND CULTIVATION 33 



film of moisture when it is in proper condition for the growth of 

 plants. The smaller the particles the greater the number in a given 

 volume of soil ; the greater the number of particles occupying a 

 given space, the more surface there is exposed for this film of 

 moisture ; and the finer the soil the more tenaciously is this moisture 

 held. This is the reason why clay soils or soils containing a con- 

 siderable percentage of clay lose their moisture much more slowly 

 than do light sandy soils. The large particles of the sandy soil 

 allow the water to leach through as well as to evaporate more 

 rapidly than is possible with the compact clay soils. 



Implements which will be found of advantage. As before 

 stated, a turning plow, a good subsoil plow which only breaks up 

 the subsoil without bringing it to the surface, a disk harrow, an 

 Acme harrow, a spike-tooth harrow, and a Meeker disk-smooth- 

 ing harrow will all be found of great service in the preparation 

 of land for trucking and market gardening. There are probably 

 no implements better suited for surface cultivation of crops in 

 the field than one-horse and two-horse cultivators built after the 

 Planet Jr. and Iron Age models. Those implements which do 

 best work stir the surface only and have numerous narrow teeth 

 rather than a few broad ones. The efficiency of surface cultiva- 

 tion lies in breaking up the crust as soon after each rain as the 

 ground can be cultivated, or as soon as there is the slightest 

 tendency to form a crust. The formation of crust indicates that 

 direct evaporation from the soil, which is undesirable, is going 

 on. Cultivation, then, should follow immediately upon noting 

 these conditions. The end to be attained in cultivation is not 

 only the destruction of weeds but the conservation of the soil mois- 

 ture by the maintenance of a soil mulch. Cultivation should at 

 all times be conducted so as to expose a minimum of soil surface 

 to the action of sun and air ; this can be secured only by level 

 culture. Cultivators which leave the land in ridges, or methods of 

 cultivation which tend to ridge or " bed up " the land, expose a 

 much greater portion of it to the action of the sun and air than do 

 the level methods. One square rod of soil, if it lies perfectly flat, 

 has only one square rod of surface exposed to the action of the wind 

 and sun. But suppose that the same area is raised into ridges 

 six inches apart and six inches high ; by computation it will be an 



