532 FIELD CROPS 



Railroads furnish one of the greatest agencies for the 

 spread of weeds, as they often carry weed seeds long distances 

 in the bedding of cars, in shipments of grain, and in other 

 material. The seeds may drop out along the right of way 

 or be cleaned out with the bedding at terminal points. In 

 the latter case, they are very likely to be transported to 

 near-by farms in manure. Many weeds first appear in new 

 localities along the railroads, and then spread to adjoining 

 fields. 



Packing material for nursery stock and other articles 

 which are brought to the farm from distant points furnishes 

 another means for the spread of weeds. Weed seeds are also 

 carried from farm to farm or from one locality to another in 

 grain and hay which are purchased for feeding. The seeds 

 pass into the manure and are then spread to the fields. 



The sowing of weed seeds with grain, grass, or clover seeds 

 is one of the most frequent methods by which the dissemi- 

 nation of these pests is effected. Seed which is grown on the 

 farm should be carefully cleaned of weed seeds to prevent 

 their spread from one field to another, and to reduce as much 

 as possible the number of weeds with which the crop has to 

 contend. Seed which is purchased should be carefully 

 examined to guard against the introduction of weeds to 

 the farm. Grain or grass seed which contains the seeds of 

 noxious weeds should be refused, or every effort should be 

 made to remove the objectionable seeds before sowing. 



702. Weed Laws. Many states have adopted laws to 

 prevent the spread of weeds. Weed control laws are of two 

 forms, those which require the destruction of certain weeds 

 along roads and railroad rights of way and, in some cases, 

 in fields, and those which are aimed to control the dissemi- 

 nation of weed seeds in the seeds of grain and grasses sold by 

 dealers. The laws in the various states differ greatly in 



