the gypsum also, the soils of the Carlsbad area were originally free 

 from noticeable quantities of alkali. The sources of the present 

 accumulations of alkali are all directly traceable to the irrigation 

 water. All recommendations for the prevention of damage by 

 alkali must, therefore, point primarily to a change in the method of 

 handling the present supply of water or of obtaining a better supply. 



DRAINAGE. 



Drainage is recommended as of most general application in the 

 Carlsbad district. Tile drains should be laid for soils in which the 

 water table rises above 3 feet. When the soil is open and dry, and 

 where seepage water has not accumulated, cultivation or growth of 

 alfalfa should be used to prevent surface evaporation and the conse- 

 quent concentration of the soil moisture. Salt determinations have 

 been made in cultivated and uncultivated ground, side by side, in 

 which the uncultivated land showed three times as much alkali as 

 the cultivated. Where salt has already accumulated, drains must 

 be laid and the salt washed out by flooding. Surface washing with- 

 out drainage is of little avail, for the first film of water dissolves the 

 salt and sinks into the ground to appear again when evaporation 

 commences. If, however, this water can pass through the soil and 

 into drains, the salt is carried away, and no further damage from it 

 need be feared. 



THE BARSTOW AREA. 



The Barstow area lies in an old lake basin, and the soils are 

 derived from the old lake sediments. The soils all contain alkali in 

 their lower depths, and in many cases are underlaid by gypsum. 



The Pecos water, where taken out, contained in June, 1899, about 

 390 parts of soluble matter per 100,000, while the Pecos opposite 

 Pecos City contained 525 parts. This concentration of the water, 

 which must be near its average condition, is so near the limit for 

 plant growth that only where the most favorable conditions of soil 

 and drainage are found can agriculture be termed successful. 



THOS. H. MEANS, 

 FRANK D. GARDNER, 



Assistants. 

 Approved : 



JAMES WILSON, 



Secretary of Agriculture. 



