No. 144.] 167 



They exclude light and heat from the young plant, and thus 

 interfere with its growth. 



They take up mineral and other matters from the soil and hold 

 them during the growing season, thus depriving the crops of their 

 use. 



Even as a green crop, they prepare the soil for the use of fu- 

 ture weeds more than for the use of crops, because they contain 

 and deposit in the soil exactly the kind of food required by the 

 same species of plants. 



It is not necessary to argue the injury done by weeds. Every 

 farmer is convinced that they should be destroyed, and the means 

 of accomplishing this are of the utmost importance. 



In the first place, we must protect ourselves against their in- 

 crease. This may be done by decomposing all manures in com- 

 post, whereby the seeds contained will be killed by the heat of 

 fermentation; or if each cord of manure has mixed with it one 

 bushel of common salt, the seeds, as well as insects, will be de- 

 stroyed ; by hoeing, or otherwise destroying growing weeds be- 

 fore they mature their seeds, and by keeping the soil in the best 

 chemical condition, for reasons which have been before described 

 by Prof. Mapes. 



The removal of weeds from the soil by the use of the hoe, cul- 

 tivator, and horse-hoe, and by the application of six bushels of 

 salt per acre for the more tender kinds, has been sufficiently dis- 

 cussed at previous meetings. 



The subject of the excrementitious matter of plants cannot be 

 too closely investigated by farmers and scientific men. If we can 

 so systematize it as to know exactly what plants will destroy 

 others, by this means we shall have in our hands a most highly 

 valuable accessory to practical farming. 



Solon Robinson— It is a very difficult thing to determine w^hat 

 are weeds and what are not. Webster defines a weed to be "Any 

 plant tli^t is useless or troublesome." The word, therefore, has no 

 definite application to any plant or species of plants; but what- 

 ever plants grow among corn, grass, or in hedges, and which are 



