AIR — WATER — SOILS. 523 



AIR— WATER— SOILS. 



Some interesting soil problems, M. Whitney (U. S. Jlcpt. A (jr. 

 Yearbook 1897, pp. 429 -440). — This is a discussion of the peculiar physical 

 properties of certain soils of the extreme West which "absorb moisture 

 so readily, lose it through evaporation so slowly, and yet supply the 

 needs of plants so regularly and abundantly that they can stand long 

 periods of drought, during which the crops coutinue to grow without 

 any signs of suffering for lack of water." 



Certain soils in the San Joaquin Valley, California, in the region of 

 Tulare and Fresno, seem to have a remarkable power of transporting 

 water for the use of crops. Less than 10 in. of rain falls during the 

 year and none falls during the growing season, and standing water is 

 probably 12 to 25 ft. below the surface; yet good crops are grown with- 

 out irrigation provided the irrigation canals are allowed to run, the 

 seepage apparently supplying in some unexplained way the water 

 needed. "At . . . Chiuo, San Bernardino, Claremont, and 

 Pomona there are certain soils upon which crops are gro^n without 

 irrigation. There are on an average between 17 and 18 in. annual rain- 

 fall at these places, the most of which falls during the winter months. 

 Less than an inch of rain falls on the average during the 5 months of 

 the growing season, from May to September, inclusive." This is an 

 artesian district, but the surface wells are from 20 to 40 ft. deep. 



Similar conditions have been noted elsewhere in the region of deficient 

 rainfall, notably "in the great wheat areas in the northern part of the 

 San Joaquin Valley of California, in the Palouse district around Pull- 

 man, Washington, and on the foothills at Wallawalla, Washington, and 

 at Bozemau, Montana, where there are soils which produce fine crops 

 of wheat without irrigation," although the rainfall amounts to from 13 

 to 18 in. and most of it falls during the winter months, and ground 

 water is from 30 to 40 ft. below the surface. 



Soils of the Mohave desert with 3 in. annual rainfall, of which only 

 0.3 in. falls in the season from May to September, were examined about 

 the middle of September, " at least 20 miles from the mountains, in the 

 midst of a level plain." 



"Contrary to expectation, the soil at a depth of from 12 to 18 in. below the surface 

 was still quite moist, in spite of the fact that no rain had fallen for at least 5£ 

 months. The surface wells vary in depth from 6 to 30 ft., occasionally being 200 ft. 

 deep. On certain parts of the desert it is the common practice to dig holes 6 to 10 

 ft. deep and allow them to fill up with water for the use of the stock. The distance 

 to water varies according to the nature of the soil, just as it does in the humid por- 

 tions of the country. The soils in which the water is close to the surface are, as a 

 rule, impregnated with alkali. There is an artesian belt under a portion of the 

 desert. 



"Investigation showed the same conditions to exist on the Nevada and Utah 

 deserts between Reno and Ogden. The annual rainfall is between 5 and 6 in., the 

 seasonal rainfall about 1 or 2 in. on the average. It is stated that water can be 

 found on these deserts about 30 ft. below the surface, although the water may be so 

 strongly impregnated with salts that it is unfit for use. . . . 



