INJURY TO CROPS AND SOIL BY WASHOE PLANT. 31 
seedlings are killed in a solution containing 1 part of copper per 
808,846 parts of water. Johnson, in his work entitled How Crops 
Grow, says: * The soluble compounds of copper, arsenic, and lead 
are very injurious to plant life, unless very highly diluted.” Other 
plant physiologists in their works confirm Johnson’s statement. 
Harter“ says: “In the case of many plants one of the most toxic 
substances known is copper, and it is more than likely that it is 
present in much of the water which experimenters have found to be 
injurious. Coupin states that one part of copper to 700,000,000 of 
water is sufficient to retard the root growth of wheat seedlings. A 
mere trace of copper is sufficient to retard growth in many cases.” 
The writer is now conducting some experiments to determine what 
amount of soluble copper in soils is injurious to the growth of certain 
plants. The work has not yet been completed, but the preliminary 
data indicate that the growth of wheat and rye is interfered with by 
the presence of 2.1 parts of soluble copper per million parts of earth 
in one soil and by 3.5 parts of soluble copper per million parts of 
earth in another soil. . 
It would appear, therefore, from these data that the Deer Lodge 
River, even at a distance of 16 to 18 miles below where the tailings are 
discharged, is not fit for irrigation purposes, and will eventually, if 
not at once, seriously injure land to which it is applied. 
It has been suggested that the Deer Lodge River already contained 
so large a quantity of alkali salts that it was injurious to soil and 
crops, even if the smelter wastes were not present. To determine 
this question, a sample of the water was subjected to an irrigation- 
water analysis with the following results: 
TABLE IX.—Composition of Deer Lodge River water (Serial No. 4244) about 
1.5 miles below where smelter waste enters. 
Determinations. Hypothetical combination. 
: a 
Parts per Parts per 
million. million. 
Bicarponic Acid 10n 24 = 5 Foes ees 2 78.73 || Calcium bicarbonate_________________ 104.59 
SIC, ACIG 10M ea es es 222i || Galen sil plate? soe <= 2. ote ee 138.00 
@hionn= =—- 2... , Se Spano 2 See Se sees 19.00 || Magnesium sulphate__ _-__._-_______ 97.34 
O-TORIG ACIC ION. 222. 8 eee 2 Woue. | Sodium: sulphate--_-=- ee 69.93 
“CE OTTER ee a Pee eee Pe Se ae 66:49 || Sodium chiorid. <2 31.35 
LEWC ety) O CEE Ce eel ee ee 19.69 
SUR 8 ee eee 35.03 
dey) AS See Ss a es 441.2] Topstl eae ee Bee 441.2] 
| | 
This analysis shows that the Deer Lodge River does not contain 
such a quantity of alkali salts as would render it unfit for irrigation 
purposes. 
*The Variability of Wheat Varieties in Resistence to Toxic Salts, U. 8, 
Dept. Agr., Bureau of Plant Industry, Bulletin 79, p. 40. 
