42 CAMPBELL'S SOIL CULTURE MANUAL 



plow with the packer, and the packer with the harrow, 

 you will have a fine, firm, moist seedbed and your wheat 

 will come up, stool and grow rapidly, and you need have 

 no fears of winter killing if the seed bed is in proper condi- 

 tion. 



Sixth: In our last is found the most important fact of all, 

 namely, that of having your ground in condition to carry 

 your crop through any spring drouth that has ever yet 

 occurred, with a sure good stand of wheat, and an early 

 rapid growth. 



SIZE OF THE DISK TO USE. 



When disk harrows first came in use the common 

 size was fourteen inches in diameter, and this size we still 

 prefer, but the demand seems to be for larger disks, the 

 farmer's conceiving the idea that they draw lighter. While 

 this is true, the pulverizing effect of the sixteen-inch is 

 not so good as the fourteen, the eighteen-inch even less, 

 and a twenty-inch we would not have on a farm. Just 

 a moment's thought on this point, and you will readily 

 see the reason 



The larger the disk the slower it revolves, consequently 

 the pulverizing effect is decreased as the size of the disk 

 is increased. I have noticed twenty-inch disks rolling 

 along when the ground was somewhat dry, and simply 

 slice the soil, raising it up a little and letting it fall back 

 in large clods in exactly the same position it was before 

 the disk passed over. The process simply made little 

 crevices and actually increased the evaporation of moist- 

 ure instead of decreasing it. A fourteen-inch disk moving 

 along at the same rate of speed would revolve faster, 

 therefore, pulverize and completelv reverse the soil. Don't 

 buy a disk too large in diameter. 



