POOR CROPS AND HOW TO GET BETTER ONES 137 



How does alkali rise in soils? Place a little dry eosin (a 

 Diamond dye) in the bottom of a tumbler; fill with soil and 

 keep it moist. This will illustrate how alkali rises in soils 

 which are irrigated. You can also use salt instead. 



How can alkali soils be re- 

 claimed ? Tie a cloth over the 

 bottom of the tumbler, crack 

 the bottom with a hammer, 

 and allow water to soak down 

 through it until the dye is 

 washed out of the soil. This 

 illustrates how alkali lands are 

 reclaimed. 



Black alkali (salsoda) is so 

 much more injurious to plants 

 than white alkali that some- 

 times, when there is but little in 

 the soil, the land may be made 

 good for all crops by putting 

 land plaster or gypsum on the 

 land. Gypsum makes the black 

 alkali " white," that is, it changes 

 it into Glauber's salt, which is 

 much less injurious than sal- 

 soda. 



Alkali water, that is, water 

 containing an unusually large 

 amount of alkali salts, should 

 not be used for irrigation if it 

 can be avoided. But if there is 

 no other water and the alkali 

 water is not excessively strong, it may be used, provided it is 

 not allowed to become stronger by evaporation at the surface. 



FIG. 74. Greasewood, a plant of 

 strongly alkaline land. 



