4 INTRODUCTORY 



The welfare of the entire people is dependent on the 

 prosperity of agriculture, and in turn agriculture rests on 

 the productivity of the soil. Human well-being is therefore 

 closely tied up with the land. Whatever affects agricul- 

 ture is important not only to the tillers of the soil but to 

 all who consume the products of the farm. In order that 

 an ample food-supply may be assured at a low price, the 

 people generally are interested in having available as large 

 a producing area as possible. 



Most of the more desirable lands of the world have been 

 settled. This means that an extension of the area of pro- 

 duction will often necessitate the use of land that has 

 some unfavorable condition. There are in the world vast 

 tracts that are not susceptible of cultivation without special 

 treatment. In the arid parts of the earth, which comprise 

 about one-half of the total land, two great conditions are 

 withholding from cultivation millions of acres of land. 

 They are drouth and alkali. The successful overcoming 

 of drouth and alkali means the addition of countless acres 

 to the productive part of the earth. It is with alkali 

 and its conquest that the present volume deals. 



It has been estimated that about 13 per cent of the 

 irrigated land of the United States contains sufficient 

 alkali to be harmful. This means that there are over 

 nine million acres of land under present canal systems that 

 are affected with alkali. There are many more million 

 acres of alkali land in the United States that do not lie 

 under irrigation systems. Similar figures might also be 

 given for other countries of this continent and for all of 

 the other continents. The alkali problem is one of no 

 mean importance to farmers, nor to any who are interested 

 in the world's food-supply. 



In a strictly chemical sense the word "alkali " refers 



