WEEDS 245 



soil. "Many fields in the older parts of the United States 

 have been abandoned at times to recuperate under this 

 slow process. With good farming, such a condition will 

 never arise. But, until our farming is much improved, 

 we may be thankful that the weeds will reclaim land after 

 man has exhausted it. 



221. The Control of Weeds. The first consideration in 

 the great majority of cases should be to secure conditions 

 that will favor the growth of the crop. Many crops will 

 grow so vigorously as entirely to smother out the weeds, 

 if conditions are favorable. But, if the conditions are not 

 just right for the crop, the weeds may overshadow it. 

 There is always strong competition between hay and small- 

 grain crops and the weeds. A very slight treatment may 

 give the one or the other the upper hand. Fig. 97 shows 

 how lime produced this difference with alfalfa. The 

 application of lime on this particular soil controlled 

 the weeds, not because it hurt the weeds, but because it 

 caused the alfalfa to grow so vigorously as to leave no room 

 for weeds. The orange hawkweed is very serious in some 

 old worn-out pastures, and farmers are wondering what 

 to put on to kill it. The real trouble is that the soil is so 

 poor for grass that almost any more hardy plant can crowd 

 it out. An application of barnyard manure and more grass 

 seed is the real remedy. 



222. The Control of Weeds in Tilled Crops. The time 

 to kill weeds by tillage is before they secure a foothold. 

 Just as the stored food in the weed seed is exhausted and 

 before it has become well rooted, a weed is very easily 

 killed. If we wait until it has become rooted, it may be 

 too late. Figs. 80 and 81 show this difference. In one 



