INJURY TO CROPS AND SOIL BY WASHOE PLANT. 



35 



While this table does not give the same results for either total or 

 soluble copper as were obtained in lOOG, it does shoAv that all of these 

 soils contain very large quantities of copper, enough of which is 

 present in a soluble form to be dangerous to, if not prohibitive of, 

 many forms of plant growth. Tt would hardly be expected that the 

 results obtained on copper, either soluble or insoluble, would be the 

 same for any two years, since it is very unevenly distributed over 

 the field and furthermore is constantly changing in its proportions 

 according: to the rainfall, irris^ation. amount of oxidation, season, etc. 

 It would only be expected that any two ^^ears would show the same 

 general condition, and this is what these analyses show. 



It has been suggested that the soils irrigated by the Deer Lodge 

 River are already so alkaline that they are unfit for growing crops, 

 and therefore the addition of copper to the soil can not make matters 

 worse. To test this point the samples of soils collected in 1906 

 were examined for the soluble salts usually present in. alkali land 

 and a determination of black alkali was made by the Skinner*^ method 

 with the following results: 



Table XII.— Soluble salt content of surface foot of soils irrigated bij Deer 



Lodge River. 



[Calculated to dry basis.] 



ACTUAL DETERMINATIONS. 



HYPOTHETICAL COMBINATION. 



Calcium bicarbonate 



Magnesium bicarbonate- 

 Calcium sulphate 



Magnesium sulithate 



Calcium chlorid 



Magnesium chlorid 



Sodium sulphate 



Sodium chlorid 



Total- 

 Black alkali. 



.303 

 .143 



.040 



.539 

 None. 



.038 



.011 

 .029 



.212 

 None. 



0.024 



.149 

 .059 



.067 

 .008 



.307 

 None. 



.547 

 .390 



.289 

 .049 



1.494 

 None. 



0.137 

 .005 



.039 



'"'002' 



'"007' 



.190 

 None. 



From these results it is evident that none of the soil samples ex- 

 amined contains any black alkali or a sufficient amount of white alkali 

 to be injurious to ordinary farm crops. 



«J. Amer. Chem. Soc, 1906, 



77. 



