CEREAL CULTIVATION GREAT PLAINS 359 



dissipated by weeds. At the Lethbridge, Alberta, Ex- 

 periment Farm, spring plowing invariably gave better 

 results than fall plowing. 



Listing in the fall and leaving the surface ridged during 

 the winter has often proved a better method than fall 

 plowing, in preparation for spring crops. Disking is uni- 

 versally the best method of treating corn ground (see 

 Fig. 96). Shepperd and Churchill (1907, p. 307) give 

 results of 3 years' experiments on preparation of corn 

 ground for wheat,, which show that spring disking was 

 better than either fall or spring plowing, the first yielding 

 at the rate of 28.8 bushels to the acre, the second 27.4 

 bushels, and the third or spring plowing 24.8 bushels. 



387. Breaking and backsetting. In many localities 

 in this area, there is yet considerable new prairie land to 

 be broken, which is invariably sown with small cereals 

 or flax. Breaking the sod where it is tough and strong, 

 as in all the middle and northern Great Plains, should be 

 done in very thin slices, before the early summer rains 

 are over. In August or September, after the sod is well 

 rotted by the rains and sunshine, it must be plowed again 

 (backset) 1 to 3 inches deeper. By following this opera- 

 tion with disking and harrowing, the soil is put in excellent 

 condition. Sometimes in the extreme north, 2 crops are 

 grown without further treatment except to burn the 

 stubble of the first crop. Use of the roller after breaking 

 will sometimes hasten the rotting of the sod (Fig. 111). 



In the southern plains, the sod is often sufficiently loose 

 that deeper breaking may be done, and cultivation very 

 soon afterward will reduce it almost to the condition of old 

 ground. 



388. The seed-bed. The advantages of a firm seed- 

 bed in this area, resulting from early plowing or listing 



