i8 Weeds. 



the cleaning cannot be accomplished by any 

 process. The only possible way of prevent- 

 ing the presence of the seeds of certain nox- 

 ious weeds in many kinds of seed grains, 

 clovers, and grasses, is to prevent them 

 from ripening in the crops which produce 

 thes'S seeds. 



5. IVeeds frequently interfere ivith a reg- 

 ular rotation. Ordinarily, farming cannot 

 be carried on successfully without a regu- 

 lar rotation. This fact is admitted on every 

 hand by the most succ^«sful agriculturists. 

 The nature of the rotation will depend upon 

 such considerations as relate to the capabil- 

 ities and requirements of the soil, the mar- 

 kets, and the facilities for ol)taining supplies 

 of plant food, ^^^he fertility of the soil can 

 always be sustained in more even balance 

 when a suitable rotation is practiced. When 

 weeds become numerous in any of the crops 

 of a rotation, they greatly hinder the prof- 

 itable growth of these crops.''/ In some 

 instances, this hindrance may be so great 

 as to render the growth of the crops of the 

 regular rotation quite unprofitable until 

 prompt measures have been taken to remove 

 the weeds. The adoption of these meas- 



