44 The Colorado Experiment Station 
application of large quantities of salt proved injurious but did not 
produce these effects. Prof. C. S. Crandall of the University of 
Illinois, also experimented on the effects of nitre but he introduced 
the solution under the bark by properly attaching a vessel filled 
with a solution of nitre to the tree. He wrote me that the result 
was the same as on the trees which I had shown him. There is 
no doubt but that the nitre in the soil is capable of producing these 
effects. The more observant and intelligent orchardists also blame 
the “black alkali” which in this case is nitre, it may be calcic, mag- 
nesic, or sodic nitrate and is probably usually a mixture of the 
three. A very simple explanation for the death of the trees suggests 
itself. The nitrates accumulated in the surface soil were probably 
carried down to the roots by a rain fall or an irrigation at a time 
when they were very active and enough of the nitre was gathered 
to do the injury. I am convinced that this simple explanation is 
the correct one. It matters not that there is arsenic in this soil. 
These trees are not affected in the least as those are which are in¬ 
jured by arsenic. These may grow thriftily until the time of their 
being killed. This trouble is not scattered through hundreds of 
orchards or even through one orchard, a tree here and there, but 
is confined to areas. See Plates II, IV and V. The orchards 
designated as Nos. 2 and 3 have been totally destroyed in parts, 
these parts of the orchards constituting an irregular but continuous 
area. Other orchards present similar conditions. Both old and 
young trees have been killed during the past season, nineteen hun¬ 
dred and nine. 
This is the only effect of this soil condition that I wish to 
present at this time though there are other serious agricultural 
conditions which I believe we will find attributable to this cause, 
i. e., to an excess of nitre in the soil. Sometimes too much at one 
time as is attested by the death of apple and also other kinds of 
trees, sometimes to too great an aggregate supply during the season. 
The following may illustrate what I mean by the latter statement. 
It is generally conceded that the application of nitrates to the sugar 
beet except in the earlier stages of its growth is detrimental to the 
quality of the beet. The following recommendation has been made 
in regard to the application of nitrates to this crop. One hundred 
and seventy pounds per acre applied in conjunction with farmyard 
manure in the fall and 245 pounds also with manure in the 
spring, a total of 415 pounds. This is applied either on the surface 
or near it and the crop is not supposed to receive further applica¬ 
tion of nitrates during the season. But what will be the condition 
of the crop if it should receive a continuous supply amounting dur¬ 
ing the season to, say, 600 or 800 pounds or is planted in soil which 
already contains several times this amount per acre. If the assump- 
