RAPE 209 



crops for reclaiming alkali lands. If the soil can be kept 

 moist by irrigation while the plants are in the seedling 

 stage the crop apparently does not suffer. Kearney (17) 

 places the limit for the saccharine sorghums between 6000 

 and 8000 parts per million of white alkali or for an almost 

 assured crop just below these points. ? He states that 

 these sorghums are among the most resistant plants when 

 in the seedling stage. An Hawaiian (5) experiment showed 

 cane to endure 3357 parts per million of alkali, mostly 

 sodium chloride, the growth being unchecked when the 

 roots of the plants were drawing from free water, but that 

 when the moisture content of the soil fell to 28 per cent 

 there was no growth on a soil containing 1980 parts per 

 million of this salt. The highest quantities of alkali on 

 which Loughridge (19) found sorghum growing unaffected 

 was 5100 parts per million of total salts, 620 parts per 

 million of sodium carbonate, 610 parts per million of 

 sodium chloride, and 3870 parts per million of sodium 

 sulphate. These limits show that where sorghums are 

 adapted they may be expected to grow on soil too strongly 

 alkaline to permit most ordinary crops to survive. 



Rape (Brassica napus and B. oleracea), while practically 

 unknown to the farmers of the United States, is a rather 

 alkali-resistant crop which is extensively used for forage 

 in Europe. The seedling of this crop is very delicate or- 

 sensitive to alkali and there is difficulty with the stand 

 where a crust is formed before the plants break through 

 the upper soil. By keeping the soil moist and paying 

 close attention to the seedlings little attention will need 

 to be given rape on account of alkali thereafter. The 

 plants withstand, and make a fair growth with, as much 

 as 6ooc to 8000 parts per million of white alkali and will 

 grow practically unchecked with 4000 parts per million, 



