COPPER AND ZINC AS ANTAGONISTIC TO " ALKALI " SALTS 1 59 
with those obtained from the cultures treated with NaCl alone and in 
many instances are equivalent to those obtained from the untreated 
soil. It is to be noted again that the smaller applications of the copper 
salt appear to be as effective antagonistic agents as the largest appli- 
cations. 
i 1 
il :i 
NoWaC L ^foHcCi' .4%NoC[ .4% NaCL .4% NqCL 4%HqCI 
MoCuCU WoCuCU50CuCL IOOCuCLzl50CuCU200CuCb 
MqCL 4%Naa r/oNaCl f)%Naa .4%WaCi .4%A/aCL 
25OCuCb3O0CuCL2 350Cua2 400CuCLa450CuCL2 500CuCU 
Fig. I. CuCU vs. NaCl. Showing the marked antagonism between the two 
sa^s for barley grain yields on the Berkeley adobe soil even to the third crop after 
one treatment. The yield from one of the duplicate pots in the third pair was lost 
as shown by the empty vial in the photograph. 
The root yields are very markedly improved in the cultures by 
addition of CuCl2 to the NaCl in all three crops and particularly so in 
the cases of the smaller additions of the copper salt. 
