FARM CROPS. 129 



between the seminal and coronal roots will depend al- 

 most wholly on the depth of planting the seed oats. 



Usually, when moisture conditions are normal, the 

 permanent roots start out about one inch below the 

 surface, but any node below the soil or even above the 

 surface, but very near to it, may throw out a whorl 

 of roots. The permanent roots soon occupy all the 

 available surface soil, since they grow rapidly, branch- 

 ing and rebranching so abundantly that the whole soil 

 area is soon filled with a mass of roots. As soon as 

 this condition is reached the roots descend at a rather 

 sharp angle. The Minnesota* and Dakota Stations 

 have found that these roots are numerous to a depth 

 of four feet, and that occasionally they may be found 

 to a depth of six or seven feet. It is supposed that 

 the purpose of these deep-growing roots is to secure 

 water. 



The Stalk (culm). The stalk of oats, wheat, rye 

 and barley is similar in all respects except in height. 

 The stalk of oats is usually a little larger in circum- 

 ference and less harsh or tough in texture than the 

 stalk of the other grains mentioned. In height, rye 

 is the tallest of these four cereals, wheat and barley 

 are practically the same height, although barley is 

 more often the shorter of the two, while oats is the 

 shortest in height of straw of any of the four. The 

 conditions of soil and climate have a greater influence 

 on the culm of oats than on wheat, rye or barley. 

 The length of the culm exerts a considerable influence 

 on the liability to lodge, and also on the ease or diffi- 

 culty in harvesting. The height and vigor of the 

 culm determines to a considerable extent the propor- 

 tion of grain to straw secured. Generally speaking a 

 height and vigor that is common, although not at all 

 invariable, yields one pound of grain to two pounds 

 of straw. 



The Leaves. The leaf of the oat plant is made up 

 of four parts: (i) The blade which is the free end 



* Minnesota Bulletin, No. 62. 



