38 Diseases of Truck Crops 



content of the best irrigating waters in the Roswell 

 district. This would give 43,560 cubic feet of water 

 on the acre, which would weigh about 2,720,000 

 pounds, and would leave on evaporation 2720 pounds 

 of salt, about one and one half tons. 



1 ' This would amount to an addition of .07 per cent, 

 of salt to the surface foot of that acre per year. If 

 this were continued about seven years, and none of 

 the salts were removed, the amount added would be 

 about .5 per cent, in the first foot of soil, which is 

 more per foot than cultivated plants could usually 

 withstand. Under actual conditions, it is probable 

 that more than one and one half tons of salts per acre 

 per year are carried to the surface in many cases, but 

 the rain washes a portion of them back and they are 

 distributed to a greater depth than one foot." 



Effect of Alkali on Plant Growth. Plants can 

 stand the baneful effect of alkali only to a limited 

 degree. The damage is always confined to the stem 

 end. Here the epidermis turns brown for half an 

 inch or more, gradually tearing away in a girdling 

 fashion. This results in the collapse and death of the 

 plant, which assumes a corroded appearance. The 

 physiological effect of alkali is to plasmolize the cell 

 contents of the bark. 



Crops Adapted to Alkali Lands. Unlike peaty 

 lands, alkali soils are adapted to very few trucking 

 crops. Sugar beets, carrots, and artichokes seem to 

 thrive fairly well in such soils. Irish potatoes will 

 thrive well in soils which do not contain more than 

 18,400 pounds of alkali per acre, of which 4000 



