TILLAGE, PLANTING, AND CULTIVATION 



399 



mulch. Some South African maize-growers cultivate between chap. 

 the rows as much as eight times in a season. To keep the maize IX ' 

 crop clean one must have the land in good condition before 

 the crop is planted, and then keep working it, never allowing 

 the weeds to get a start. This subject is more fully discussed 

 in chapter X. 



For these reasons the small maize farmers of the United 

 States who give their crop thorough cultivation, obtain heavier 

 returns per acre than those who grow maize on a larger scale 

 and are unable to give it the same attention. Prof. Carver 

 notes (cf. IT 6) that there is a noticeable general decline in the 

 intensity of cultivation of the maize crop, with the increase in 

 size of farm in the Western States. There is also a noticeable 



Fig. 147. — -"New Western" cultivator. (Courtesy of Messrs. 

 Malcomess & Co.) 



decrease in yield per acre ; that this is associated with the less 

 intensive cultivation rather than to geographical reasons, is 

 indicated by the fact that the highest average yields per acre 

 are obtained in the North Atlantic States, quite out of the 

 Maize-belt (IT 41). 



Care should be exercised in the use of the cultivator, for 

 if it is set too deeply, or run too close to the plants, it may 

 prune off a proportion of the roots, below the surface, which will 

 probably reduce the yield below the potential ; for this reason 

 some American Stations recommend that after the first cultiva- 

 tion the implements should not be allowed to cut deeper than 

 2 inches; deep cultivation also tends to turn up a fresh crop 

 of weed seeds. 



