ALKALI SOILS 343 



method of alkali eradication is never very efficient, and is often 

 dangerous, as it encourages the presence of very large amounts 

 of alkali salts in the surface soil. 



Often alkali accumulations may be washed from the soil sur- 

 face by turning on a rapidly moving stream of water. The tex- 

 ture of the soil, as well as the slope of the land, must be just 

 right for such a procedure. Generally so much water enters 

 the soil that the land remains heavily impregnated with alkali 

 salts. Both this method and the previous, even if successful, 

 are only temporary. Moreover, lands carrying so much alkali 

 as to admit of either one of these procedures may be so heavily 

 charged as never to yield to any form of either eradication 

 or control. 



182. Control of alkali. — Where excessive amounts of 

 soluble salts do not exist in a soil the control of the alkali with 

 a view of keeping it well distributed in the soil column is the 

 best practice. The retardation of evaporation is, of course, the 

 main object in this procedure. The intensive use 6f the soil- 

 mulch is, therefore, to be advocated, especially in al] irrigation 

 operations where alkali concentrations are likely to occur. 

 Such a method of soil management not only saves moisture, but 

 also prevents the excessive translocation of soluble salts into 

 the root zone. This method of control is the most economical, 

 the cheapest, and the one to be advocated on all occasions, no 

 matter what may have been the previous means of dealing with 

 the alkali situation. Certain soils that are strongly impreg- 

 nated with alkali may be gradually improved by cropping with 

 sugar-beets and other crops that are tolerant of alkali and 

 that remove large quantities of salts. This is more likely to be 

 efficacious where irrigation is not practiced. Certain crops, 

 moreover, while somewhat seriously injured when young, are 

 very resistant once their root systems are developed. A good 

 example is alfalfa, the young plants being very tender while 

 the mature ones are extremely resistant. Temporary eradica- 



