STEPPES, DESERTS, AND ALKALI LANDS. 609 



of Kentucky, the black prairies and " bluff "-lands of the Missis- 

 sippi Valley, and hundreds of local examples. The common and 

 beneficial practice of "marling" noncalcareous lands illustrates 

 the same axiom. It logically follows that, inasmuch as actual 

 examination shows practically all arid soils to be calcareous, " arid 

 countries are rich countries " whenever irrigated ; and the actual 

 and concordant experience of mankind corroborates the con- 

 clusion. 



In other words, the ancient civilizations have, consciously or 

 unconsciously, chosen countries having naturally rich and durable 

 soils, capable of supporting for a long time a denser population 

 than the forested regions, without resort to artificial fertilization 

 beyond irrigation. This seems to be the simple and rational ex- 

 planation of their marked preference for arid countries; and 

 unquestionably Egypt owes its perennially undiminished produc- 

 tiveness at least as much to its arid climate as to the alluvial de- 

 posits brought down by the Nile, as is shown in the oases of the 

 Libyan Desert, as well as in India and China. 



But if these things are true, then the steppes and alkali lands 

 deserve the most earnest attention, both of agriculturists and of 

 students of natural economy ; for in them lie possibilities for the 

 abundant sustenance and prosperity of the human race that have 

 thus far been almost left out of account. While it is true that 

 irrigation water may not be practically available for the whole of 

 the arid regions of the globe, so much remains to be done in the 

 study of the most economical use of water, of appropriate crops 

 and methods of culture, that even an approximate estimate of 

 actual possibilities in this direction can not yet be made. At 

 all events, it is of the highest interest to study the problem 

 of the reclamation of these intrinsically rich lands in all its 

 phases. 



Foremost in this problem is the question of the manner of 

 dealing with the " alkali " salts, which, as experience proves, exist 

 not only on the spots where they naturally show on the surface, 

 for as soon as irrigation is practiced they appear at numerous 

 points where no symptoms of alkali were noted before. Some- 

 times, indeed, the entire area of large farms may in the course of 

 years become thus afflicted, so that orchards and vineyards that 

 have been in bearing for a number of years become stunted, and 

 in spots even perish. 



Examination of the manner in which such injury comes about 

 shows that it is rarely due to direct action of the salts on the 

 roots. Almost always the injured part is at or near the root- 

 crown, or base of stem or trunk ; proving that it is the result of 

 accumulation of the salts at the surface (so often obvious to the 

 eyes), in, consequence of evaporation. 



VOL. XLVIII. 43 



