EGYPTIAN COTTON AS AFFECTED BY SOIL VARIATIONS. 



23 



were several areas of greater or less size where the plants either had 

 failed to appear or had subsequently died. The electrical resistance 

 of the soil was determined in different parts of this field on October 

 23, and notes were made upon the character of the plants where the 

 respective soil samples were taken. The results of these observa- 

 tions are summarized in Table IV. The percentages of total salts 

 indicated by the electrical resistances as given in this table are 

 computed from Table III, page 14, Bulletin 61 of the Bureau of Soils, 

 which applies to a type of alkali consisting of one-half chlorids and 

 one-half sulphates. 



Table IV. — Electrical resistance of the saturated soil, indicated percentage of total salts, 

 and condition of Egyptian cotton plants, at Bard, Cal., in 1911. 



Inspection of this table shows no close relation between the salt 

 content of the soil and the growth of the cotton plants. Thus, at 

 boring No. 2, located midway between two plants which were about 

 as good as any in the field, the first foot of the soil contained con- 

 siderably more soluble salts than the first foot of borings Nos. 1, 3, 

 and 5, where there were either no plants at all or the plants were evi- 

 dently suffering. 1 



1 Much of this alkali had doubt less accumulated in the upper soil after the cotton was planted, the groimd 

 water table in this field having reached the surface of the soil during the high-water stage of the Colorado 

 River in June. It had lowered by the date when these borings were made, saturated soil having been 

 encountered at a depth of about 4i feet in the neighborhood of boring No. 3. 



[Cir. 112] 



