6i 4 POPULAR SCIENCE MONTHLY. 



vest time most of the soil moisture was exhausted, only a moder- 

 ate efflorescence of alkali was seen on this land even late in the 

 season. 



It is thus obvious that when by any means a good " stand " of 

 a leafy perennial crop with deep roots, like alfalfa, can be obtained 

 011 alkali land, the rise of the salts resulting from irrigation is 

 measurably checked, and may remain wholly innocuous so long 

 as that crop occupies the soil. Experience amply confirms this 

 conclusion ; but the difficulty of obtaining such a stand is often 

 very great, especially on " black " alkali land, which " rots " the 

 seed as often as sown. It is then that the use of gypsum to neu- 

 tralize the carbonate of soda often becomes the saving clause, 

 enormous crops being then grown on land formerly considered 

 worthless. Diagram No. 5 may illustrate this in the case of 

 wheat, which was grown in 1892 at the Tulare Station on ground 

 that, prior to the reclamation work, would hardly grow even 

 " alkali weeds," but then yielded grain at the rate of forty-five 

 bushels per acre. 



The diagrams, however, convey unanimously the fundamen- 

 tally important lesson that the amount of alkali salts in these soils 

 is limited, and lies within such easy reach of the surface that ordi- 

 nary underdrainage at the depth of from three to four feet will 

 relieve these rich soils of their noxious surplus, once for all. Also 

 that toward the end of the dry season the removal of a few 

 inches of surface soil will go far toward relieving the land of 

 the same. 



A few words should be said in regard to the kind of the salts 

 as well as their quantities. As regards the main ingredients, 

 which may be considered as useless or harmful to vegetation, 

 inspection of the diagrams shows that in no case is the noxious 

 carbonate of soda as abundant near the surface as in the case of 

 the subsoil hardpan in Diagram No. 1. Investigation has shown 

 this to be due to the aeration which occurs near the surface ; 

 while, on the contrary, in a water-logged soil, the " black " alkali 

 is constantly in progress of formation from the "white" or 

 neutral salts. Hence we find the worst of the " black " cases in 

 low or badly drained ground, and in close soils. Here, again, 

 underdrainage affords radical relief. 



But underdrainage and washing-out of the salts would in 

 many cases be like " throwing out the child with the bath." For, 

 as has been stated at first, not only the useless but also the useful 

 or plant-food ingredients, which the farmer purchases in the form 

 of fertilizers, are present in them. They not unusually contain as 

 much as twenty per cent of salts of potash, ten to twenty per cent 

 of saltpeter, and several per cent of soluble phosphates. In one 

 notable case the equivalent of one ton of Chile saltpeter (worth 



