144 The Sugar-Beet in America 



of water or to the time of application. In the weekly 

 irrigation tests, the beets that were not irrigated had the 

 largest number of forked roots, whereas in the plats that 

 had water applied at different periods, the plat receiving 

 water only at the first stage had the least number of forked 

 roots. The greatest number was on plats irrigated early 

 and late. The differences, therefore, are not consistent and 

 the idea that any method of irrigation greatly increases 

 the tendency toward forkedness seems unwarranted. 



An examination of Figs. 20 and 21 for the effect of 

 treatment on the height of tops reveals a rather close 

 relationship between this and the yield of tops, but not 

 the yield of beets, which has already been discussed in 

 connection with Figs. 14 and 15. 



DRAINAGE 



Reasons for drainage. (Fig. 22.) 



Many millions of acres of land in the United States 

 contain so much water that crops cannot be raised suc- 

 cessfully. Part of this land is in permanent swamps; 

 some of it is dry during a part of the year, being water- 

 logged only at certain seasons. Much land, having a dry 

 surface appearance, contains ground-water so near that 

 roots cannot penetrate to any great depth. The chief 

 difficulty in the way of successful agriculture in all such 

 places is the surplus of water. The only way to make 

 this land suitable for crops is to drain it. 



In most arid regions, much of the land contains a high 

 percentage of soluble salts. These often accumulate near 

 the surface in such large quantities that the growth of 



