262 IOWA DEPARTMENT OP AGRICULTURE. 



Many successful corn growers have found it very profitable to continue 

 cultivation after the corn is too nigh for the regular two-horse culti- 

 vators. They go between the rows with a one-horse cultivator, or drag, 

 while the ears are setting, and thus maintain a dust mulch. This work, 

 is of value only in the dry season. 



Root-pruning or cutting off the roots of the corn plants effects serious 

 injury to the crop and demands the thoughtful attention of the majority 

 of corn growers. The loss from this source is so great and yet so fre- 

 quently entirely overlooked that We desire to offer a few figures which 

 will clearly show the importance of a system of cultivation which does 

 not cut and injure the roots of the corn plants. 



The results of three years' work in testing the effects of root-prun- 

 ing were as follows: 



Not pruned 62 bushels per acre 



Pruned two inches deep 60 bushels per acre 



Pruned four inches deep 45 bushels per acre 



Pruned six inches deep 30 bushels per acre 



The experiments explain the reduction of the yield which almost 

 invariably follows deep cultivation. 



SEED CORN BREEDERS. 



The third factor in the growing of a corn crop is the seed corn. It 

 is in this connection that the possibilities in corn breeding are most 

 pointedly emphasized. With few exceptions, only in the past decade 

 have earnest euorts been put forth in the way of systematically breed- 

 ing corn. More than half a century ago a few men, realizing the far- 

 reaching importance of well-bred seed corn, began to improve their 

 Btrains of corn by careful selection and cultivation. Their labors, pros- 

 ecuted amid innumerable difficulties and discouragements, finally gave 

 to the corn growers of the United States improved varieties of corn. 

 They are today the very foundation on which rests much of the advance- 

 ment which has been made in establishing our most valuable pure-bred 

 varieties of corn. One of these pioneer breeders, J. S. Learning, of Wil- 

 mington, Ohio, as early as 1825 began to select and breed the variety 

 which now bears his name. This corn was brought to Illinois, the shape 

 and size improved by selection and breeding for desirable characteristics, 

 and today this variety is the most widely grown of all yellow varieties. 

 The valuable results accruing from these long years of breeding are 

 proved by the records made by the Learning corn in a series of compara- 

 tive variety tests of yields per acre which began in 1888 at the Illinois 

 experiment station. During this long period this variety has maintained 

 its lead as the best yielder. Another pioneer breeder, Mr. James Riley, 

 of Thorntown, Indiana, more than a quarter of a century ago selected 

 the best white corn in his state for a foundation line and by persist- 

 ently weeding out the barren stalks and other undersirable types in his 

 corn fields he s .cceeded in producing the valuable strain of corn known 

 as the Boone County White. This variety is widely grown and has been 



