DISTRIBUTION OF SEEDS 377 



the fields is much less attractive to visitors or others contemplating 

 purchase or rental of that particular farm or others in the vicinity. 



Weeds Are Sometimes Beneficial. If it were not for weeds, 

 many farmers would not practice rotation of crops. Indeed, rotation 

 is one of the very best ways for the control of certain classes of weeds. 



Cultivation of the soil is required because of weeds. Many 

 a poor farmer would neglect the crops if it were not for the growth 

 of weeds which he feels in duty bound to kill by cultivation. The 

 other benefits arising from the cultivation, such as the aeration of 

 the soil and the saving of moisture, would not be realized if the 

 farmer were not forced by weed growth to continue to cultivate 

 corn, potatoes, garden truck and garden crops. Some one has 

 said that ' 'weeds make lazy men more diligent. " 



Weeds may serve as feed for animals, as they are often eaten 

 by sheep, pigs, cattle and horses. 



Certain succulent weeds are used by man as greens, particu- 

 larly in the spring of the year. 



Cover crops are often found to consist entirely of weeds of 

 one or more kinds. Nature tries to cover the soil wherever it is 

 left bare by man. This is no small benefit arising from weed 

 growth. The growth of a cover of weeds not only serves all the 

 purposes of a cover crop but it produces a cover of green manure 

 which may be turned under for the improvement of the soil before 

 the next money crop is started. 



Plant food which is leached into the subsoil is often recovered 

 by the growth of deep-rooted weeds reaching their tap roots into 

 the subsoil and feeding upon those elements which are out of 

 reach of most of our field crops. This plant food thus recovered 

 may be made available for succeeding crops by the use of the 

 weeds as green manure. The deep-rooted weeds may also be 

 credited with the benefit arising from soil aeration and the forma- 

 tion of water channels along the many deep roots. 



No one should defend the growing of weeds for the purposes 

 here mentioned. The careful farmer will grow other crops which 

 will accomplish each of these purposes better. 



Dissemination of Weeds. There are two main ways for the 

 spread of weeds as well as of other plants. (1) By seed distribu- 

 tion, and (2) by the growth of vegetative parts, such as runners, 

 rootstalks, and bulblets. 



Distribution of Seeds. There are a number of provisions in 

 nature for the spread of seeds. The snapdragon throws its seed at 



