30 



began to fail. The most natural way to remedy the evil was to re- 

 move what he saw; this he evidently did as piles of earth containing al- 

 kali are to be seen in the districts where alkali exists. While tempo- 

 rary relief was gained by this process, conditions were constantly be- 

 ing made easier for increased accumulations, since every time he scrap- 

 ed the soil, the level of that particular spot was lowered.* 



APPEARANCE AND DETECTION OF ALKALI AREAS. 



In an uncultivated soil it is not always easy to distinguish an alkali 

 spot. There are signs, however, which may indicate its presence. If 

 certain grasses which prefer alkali soil are found in the field among 

 other plants, it is safe to say that the land on which they grow is al- 

 kaline. This is especially true for some of the salt grasses. If an area 

 is without growth, and the first surface inch or two of soil is in the 

 form of a fluffy powder that burns tbe tongue, it will usually be found 

 to be alkaline. 



After a soil has been turned over by the plow it is impossible to 

 distinguish the alkali > prior to irrigation. After an irrigation, 

 it is easily discerned either by a white incrustation on the surface, a 

 dark brown color in patches, or by areas of soil whose surface layer 

 remains moist long after the irrigation period. These moist spots are 

 particularly in evidence in the early morning, evening, or on a foggy 

 day. 



If a soil after being wet and dried becomes exceedingly hard and 

 difficultly worked with the plow, it is partial evidence that alkali 

 of a particular type is present. 



A strongly alkali spot in a field of cane may sometimes be detect- 

 ed by the appearance of the cane growing on it. The cane will seem 



(*) The ancient inhabitants of Peru have had some influence on modern agricultural 

 conditions. The country must have been thickly populated in their time as signs of their 

 labors are to be seen in localities that would hardly have been selected but for overcrowd- 

 ing. It is said they terraced the mountains in order to get lands to plant crops. They 

 built dams to control the water, and they constructed long water ways to distribute the 

 water to land that would otherwise be unproductive. In fact, they seem to have devel- 

 oped agriculture as then known to its f uUest extent. They raised many crops of which 

 corn seems to have been one of the most important. It is said they knew the value of the 

 guano and that the seabirds that helped to make it were held sacied. By changing the 

 course of the irrigating waters, they have altered somewhat the area of cultivable land. 

 Some of the soils have been made better by their cultivation, and some have been injured 

 because toy their methods of scraping and irrigating, the alkali has been increased. 



