The Soil. 61 



of the delicate root fibres and consequently greater room for root 

 growth. It increases the surface to which the roots are exposed 

 and necessarily gives the developing plant a larger feeding area. 



Tillage hastens chemical changes in the soil by bringing to- 

 gether particles which have not before been in contact. Par- 

 ticles with different chemical properties are thus enabled to act 

 upon each other. 



The changes induced by freezing and thawing may also be 

 greatly increased by proper tillage. Fall plowing exposes the 

 large lumps to the influence of the weather during the winter. 

 This disintegrates the clods and improves some classes of soils 

 in a remarkable manner. It also tends to save the moisture, as 

 the loose ground turned up by the plow prevents loss of water 

 by evaporation. The broken uneven surface also favors a greater 

 absorption by the soil of the winter rain or snow. In an experi- 

 ment at the Wisconsin Station, a plot plowed in the fall con- 

 tained 1.15 acre inches more water than an adjacent plot not 

 so plowed. It must be remembered that fall plowing may not 

 always be the best practice, as hard soils, low in humus, may be 

 badly puddled if fall plowed. Plowing the ground very early in 

 the spring is a rational practice, for there is no other season when 

 tillage is so effective in conserving the soil moisture. Experi- 

 ments indicate that in soils where such practice has been fol- 

 lowed, the moisture content will be greater than in those un- 

 plowed. Judgment must be exercised, however, in the choice 

 of time in order that no injury to the texture may follow. 



By the action of the plow, the residues of crops, weeds and 

 manures are buried, and incorporated with the soil. The deep 

 tillage of heavy land allows rain to penetrate it and establishes 

 the drainage of the surface soil, and increases the temperature. 



A shallow surface tillage preserves the moisture of the soil in 

 time of drought. It lessens the evaporation from the surface by 

 breaking the capillary connection with the store of water below 

 the surface. After a rain this will be again established and 

 the cultivation should be repeated as soon as possible. Such a 



