CULTIVATION. 107 



have shown that land well harrowed will yield better 

 crops than land poorly harrowed, but supplied with a 

 greater quantity of fertilizers. 



Rolling. — Rolling is a useful process in tillage under 

 certain circumstances. It crushes and pulverizes lumps 

 of soil which have escaped the work of the harrow. 

 When the soil is very dry and loose, rolling ])resses it 

 more compactly about seeds, bringing them moisture by 

 capillary action, and hastening their germination and 

 growth. It serves a good purpose in the spring, by 

 pressing into the soil the roots of grass which have been 

 thrown out by the action of frost. Clayey land, when 

 wet, is injured by rolling, as the i)articles of soil are 

 pressed too closely together to admit air, and in drying 

 form a hard crust uj)on the surface. 



Cultivating. — The frequent cultivating or stirring of 

 the surface soil between the rows of hoed crops, during 

 the period of their active growth, is beneficial, both liy 

 killiug weeds as soon as they appear, and preventing 

 the loss of moisture. In every shower and rain-storm 

 the })articles of soil are washed and Iteaten together so 

 compactly as to cause moisture to rise to the surface 

 by cajjillary action and evaporate. By loosening the 

 surface soil repeatedly, this is prevented. 



As the rootlets of plants ompletely fill the soil, ap- 

 proaching very near to the surface, this cultivation should 

 generally be shallow. While the surface soil which is 

 stirred in cultivation retains the moisture beneath, it 

 becomes drier itself because of its loose condition. 



By cultivating deeply among crops, we may ])revent 

 roots from occupying the upper portions of the soil, not 

 only by repeatedly breaking them, but by rendering this 

 })art of the soil too dry. 



