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the soil loose and open, and in many, cases their seeds gathered 

 with the crop injure its value. Weeds should not be allowed 

 to grow even in the borders of cultivated grounds, since from 

 this point they may seed the soil for several years to come. 

 In this connection it is well to remember the oft-quoted 

 maxim, " One year's seeds, seven years' weeds." 



Photograph from American Steel and Wire Co. 



FIG. 115. A grainfield showing wild mustard in blossom. The portion on 

 the right has been sprayed with iron sulphate 



Nature of weeds. Some of the qualities that conduce to 

 weediness in plants are abundant and easily distributed seeds, 

 the ability to grow rapidly, to endure injury and shading, and 

 to thrive upon little moisture and in sterile soils. Many secure 

 immunity from grazing animals by offensive odors, prickly 

 leaves and stems, and other disagreeable characteristics. Some 

 are winter annuals that grow in spring before more valuable 

 crops have started ; others are summer annuals that wait until 



