B. P. I.— 757. 



THE WEED FACTOR IN THE CULTIVATION 



OF CORN. 



INTRODUCTION. 



Corn is one of the most important crops in the United States. 

 Cultivation is one of the most expensive operations in the production 

 of corn. It is also the operation which, of all phases of corn growing, 

 has probably received the least study or about which we have the 

 least fundamental knowledge. 



The soil-mulch theory of tillage has been a fundamental one in 

 American agriculture. It was long ago found that by means of a 

 mulch crops could be grown in alternate years on land receiving such 

 scant rainfall as to make it impossible to grow any satisfactory crop 

 by other methods. In studying the effect of the mulch it has come 

 to be generally recognized that in most soils moisture can be saved 

 by maintaining the top portion of the soil in a finely divided con- 

 dition. It has also been found that frequent stirring of the soil pro- 

 motes rapid nitrification. It would seem to follow naturally that a 

 system of cultivation which promotes nitrification and conserves 

 moisture would be an extremely valuable system to apply to a tilled 

 crop. In practice it has been found that in most cases frequent 

 shallow cultivation gives better yields than other methods of corn 

 tillage. Upon this experience tillage philosophy has been developed 

 and tillage practice based. 



In this publication data are presented with reference to the weed 

 factor in corn cultivation. A direct comparison has been made 

 between what is considered the ideal method of cultivation for corn 

 in each section in which the experiment was conducted and simply 

 removing the weeds without stirring the soil or producing a mulch. 

 The measure of the relative merits of the two systems has been, not 

 in the preservation of soil moisture, or the effect on nitrification, 

 or the making available of plant nutrients, but the relative yields 

 of corn produced. 



Experiments aggregating 125 scattered over 28 States are here 

 recorded. Of this number 12 have previously been recorded in 

 experiment-station literature. A study of the results obtained in 

 these 12 early experiments made it seem desirable to take up in a 



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