212 DRY FARMING 



of farmers are being visited on the present occupants of 

 the land. Under these conditions it is generally a 'dif- 

 ficult problem to control weeds and at the same time 

 make a profit from the farming operations. 



168. Why Weeds are Harmful.— 



(1) Weeds dissipate soil moisture (approximately 



500 lbs. for every lb. of dry matter they produce). 



(2) They use plant food that otherwise might go to the 



production of crops. 



(3) They lower the yield of crops by crowding and 



shading. 



(4) They lower the value of grain by causing it to be 



"docked" or to grade "rejected". 



(5) They render seed unfit for sowing or cause extra 



expense in cleaning for seed purposes. 



(6) They increase the cost of tillage, twine, stooking, 



threshing and freight. 



(7) They lower the value of the farm. 



(8) Some weeds are poisonous. 



169. Some Good Points About Weeds.— Yet weeds are 

 not always harmful nor even useless. The weeds that grow 

 on fallowed land pAmp tons of moisture from it, but 

 when they are plowed under they add organic matter 

 to the soil. This is seldom a sufficient excuse for weeds 

 in dry areas, even though the backward farmer may 

 find some consolation in the fact. The moisture saved 

 through the prevention of weeds growing on a fallow is 

 generally of more value to the soil than the organic 

 matter the weeds would produce. Nevertheless, the 

 plowing under of weeds increases the ultimate producing 

 power of the land, and on soils that need organic matter 



