THE SALT CONTENT OF COTTON FIBER 1 
By Thomas H. Kearney, Physiologist in Charge , Alkali and Drought Resistant 
Plant Investigations , and C. S. Scofield, Agriculturist in Charge , Western Irri~ 
gation Agriculture , Bureau of Plant Industry , United States Department of 
Agriculture 
It has been reported that the fiber of Pima cotton, a long staple variety of the 
Egyptian type grown under irrigation in Arizona, is difficult to spin when the 
humidity of the air is high. The suggestion has been made that this might be 
due to a high salt content of the fiber, attributable to the fact that irrigated land 
in the Southwest often has a higher salt content than most of the soils on which 
cotton is grown in the Southern States. 
Determination of the actual salt content of Pima fiber therefore seemed ad¬ 
visable. For this purpose samples of this cotton were collected in 1923 at the 
United States Field Station at Sacaton, Ariz., together with samples of other 
types of cotton grown at the same station. Samples (for which the writers 
are indebted to D. M. Simpson of the Office of Crop Acclimatization and Adapta* 
tion, Bureau of Plant Industry, United States Department of Agriculture), were 
also obtained from James Island, S. C., to permit a comparison of eastern-grown 
with Arizona-grown cotton. 2 In order to avoid contamination with dust, the 
fiber was extracted from bolls which were mature, as shown by the fact that they 
were beginning to crack at the tip, but in which there had been no opportunity 
for dust to accumulate. 
The fiber which enters commerce is picked from fully open bolls and usually 
accumulates some dust before it is gathered. If commercial Pima cotton showed * 
an abnormally high salt content, this might be due to the deposition of dust on 
the fiber in the open bolls, rather than to absorption of salt from the soil solution 
through the roots of the plant. To test this possibility a sample of dusty Pima 
fiber was collected from fully open bolls at the edge of a field near a road. 
Determinations of salt content of the fiber were made on samples collected 
from the following eight plantings of cotton, the fiber having been extracted from 
ripe but unopen bolls in all cases except A: 
A. —Pima Egyptian, open bolls, fiber dusty, Peoria, Ariz. 
B. —Pima Egyptian, plants stunted by alkali, Sacaton, Ariz. 
C. —Pima Egyptian, well-grown plants in good soil, Sacaton, Ariz. 
D. —Sea Island cotton, growing adjacent to C. 
E. —Meade Upland cotton, growing adjacent to D. 
F. —Lone Star Upland cotton growing near C, D, and E. 
G. —Sea Island cotton from James Island. S. C. 
H. —Meade Upland cotton from James Island, S. C. 
Each sample of fiber was divided into two subsamples, one being used for 
determination of the water soluble salt content and the quantity of ash not 
soluble in water, the other for determination of the total ash. 
1 Received for publication Mar. 20, 1924. 
8 The soil of the low-lying islands off the coast of South Carolina probably has a somewhat higher con¬ 
tent of sodium chlorid than most cotton soils of the Southern States, but the locality where these samples 
were collected is typical of the area which produces the choice “crop lot" Sea Island cotton. 
Journal of Agricultural Research, 
Washington, D. C. 
( 293 ) 
Vol. XXVIII, No. 3 
April 19, 1924 
Key No. G-392 
