262 TvvENTv-sEvENTH Annual Report 



The effects of another season's work will undoubtedly shed much 

 light on the situation, and it is inadvisable to draw too many conclu- 

 sions at this date. However, certain points have been definitely noted 

 and certain results have been obtained which are of interest. A discus- 

 sion of these follows : 



The matter seems to resolve itself into Johnson grass control rather 

 than eradication. Irrigating water brings in enormous quantities of 

 seed each summer, and plants from this source must be continually dealt 

 Vv'ith in the absence of a suitable method for screening out these seeds. 

 It is as easy to control a seedling Johnson grass plant as any other weed, 

 provided the work is done in time. As a usual thing the propagating 

 rootstock starts to develop about the time the head is in the boot, or 

 just before it appears above its protective sheath. Before this time a 

 single cultivation destroys the plant. It follows, then, that after the old 

 rootstocks are destroyed the key to the whole matter is to attack the 

 seedlings before they have had time to develop rootstocks of their own. 



The cost involved where the grass is kept down by intensive culti- 

 vation is very heavy, but the returns are often great enough to leave a 

 margin of profit. By this method, the farmer can eventually get his 

 place well rid of this pest without being denied the use of his land ; and, 

 by doing a large share of the work himself can accomplish the task 

 without much outlay of actual cash. If this method is to be successful, 

 he must have a cultivator that cuts every bit of plant material between 

 the rows, and he must be able to do the work immediately when the 

 necessity arises. When leaves are formed above the ground, this por- 

 tion of the plant begins to feed the rootstock, and the only way to make 

 any headway is to destroy the growth while the rootstock is feeding 

 the above ground portion. If this is done the vigor of the rootstock is 

 diminished during the best growing season at a surprisingly rapid rate. 



Dry fallow is not as quick a method as intensive cultivation. A 

 heavy rain may cause enough growth before the field can be entirely re- 

 plowed to restore otherwise depleted rootstocks to normal vigor. Plow- 

 ing in dry ground in hot weather is very expensive and slow work, and 

 the farmer has a difficult situation to face when he has to bear this 

 expense on land that is returning him no income. 



Pasturing with sheep promises to be a favored method. The suc- 

 cess of this depends on overgrazing. That is, enough sheep must be 

 run on a field to graze every bit of the grass as close to the ground as 

 possible. When the land has an abundance of water and the proper 

 temperature to induce fast growing, the rootstocks can be very rapidly 

 weakened. Sheep have the alditional advantage of keeping ditches 



