60 



FIELD CROP PRODUCTION 



ing capacity and preventing the soil from becoming hard 

 and compact. Barnyard manure is sometimes applied 

 to the grass land in the spring, thus benefiting both the 

 hay and the corn, or it is applied to the meadow after 

 the hay is cut, and turned under for corn. Soils that have 

 been under cultivation for a long time, or that are naturally 

 deficient in some of the elements of plant food, may be 

 greatly benefited by the addition of commercial fertilizers 



FIG. 15. Unfertilized and fertilized corn plots grown in continuous 

 culture for 18 years. 



to supplement the barnyard manure. No certain fer- 

 tilizer can be recommended as the best corn fertilizer. 

 Some fields require one element of plant food or a mixture 

 of fertilizing constituents, while others may require quite a 

 different treatment. In other words, the soil should be 

 fertilized and not the corn. When commercial fertilizers 

 are applied to corn land, they should be broadcast or 

 drilled in with a fertilizer drill. The practice of sowing 

 the fertilizer into the hill with the corn is not to be recom- 

 mended, since the corn roots will find plant food so close 



