5S 
Colorado Experiment Station 
Our observation is that the bad effect of ‘'white alkali” has been 
greatly over-estimated. There is, undoubtedly, a limit to the amount 
that may be present in a soil without danger to the crops, or trees 
grown on the land, but this limit is so high in the case of our soils that 
the danger line has not been observed. 
I 
We have not observed the death of any plant which we could with 
certainty attribute to “white alkalis”, though we have seen some alkalis 
quite rich in magnesic sulfate. 
The “black alkali”, sodic carbonate, is very generally present in 
small quantities as a direct product of the action of carbonated waters 
on the rock particles, whether in the mountains or in the soils, but it 
passes into the drainage of the country to such an extent as to prevent 
its accumulation except under unusual conditions. 
In one section of the State, which has been presented quite fully, 
unusual conditions occur and the “black alkali” has accumulated in in¬ 
jurious quantities. Irrigation by flooding, and the application of gyp¬ 
sum will probably lessen this evil but cannot be expected to wholly 
remedy the trouble. 
The nitrates cannot properly be considered as alkalis in the sense 
that we use this term, but inasmuch as they are usually mistaken for 
“black alkali”, and are injurious to crops, in the quantities that they 
occur in places, they have been discussed. 
These nitrates are not derived from the rocks but are formed in 
several successive steps through the agency of small plants or micro¬ 
organisms which are present almost everywhere but which are much 
more active in our soils, especially in particularly favorable spots, than 
is usual. 
, “Black alkali”, sodic carbonate, in small amounts, is said to favor 
the activities of these plants. The amount of sodic carbonate required 
to retard their development is greater than that which will injure the 
ordinary cultivated plants. 
