The Fixation oe Nitrogen. 67 
spring of 1911, in fact a number of trees have been dug up in this 
portion of the orchard, just how many I do not know, but all of 
the trees shown in our photographs taken in October, 1910, seventy- 
five of them, have been removed, but by June 3, 1911 many more 
trees, nine rows in all, back from the foremost row in Fig. 2, 
Plate IV have died since August 18, 1910. All of this land 
is in good physical condition, mellow, well cultivated and free 
from water. 
The white alkali collected in August, 1910 shows no nitrates, 
that collected from a very bad spot, in October, shows a rather 
small percentage, 4.017, and as this was surface alkali and soil it 
does not necessarily indicate a large aggregate amount. The 
samples of soil taken where there was no white alkali, while giving 
a low percentage of water-soluble, showed the presence of very 
large amounts of nitrates, 21.377 an d 26.640 percent. While the 
trees did not die last year, 1910, where these samples were taken, 
they did die in May of 1911 as soon as the trees put out their 
leaves. 
All of these trees and all others referred to through this and 
previous bulletins as having been killed by nitre, die in the same 
manner, with the symptoms produced by the direct application of 
sodic nitrate. 
The water samples in this case are particularly interesting. 
The samples taken from the cellar, one in August, the other in 
December, 1910, are both quite rich in nitrates. The richer one 
of the two carrying approximately one and a third tons per acre- 
foot of water. The important question is whence these nitrates ? 
The water had begun to come into this cellar about twenty three 
months prior to the taking of the last sample and the significance 
of the results depends upon the answer given to this question. The 
natural, and in this case, correct answer is unquestionably from 
the surface. The sample of water, No. 1041, taken from a hole 
sixteen feet deep in all, is very much richer in total solids but 
contains no nitrates. I take it that this represents the ground water 
proper of the section and agrees with the ground water proper of 
other sections showing that the nitrates are not transported to the 
affected areas by this means. 
The destruction of this orchard has proceeded very rapidly. 
It began in the early summer of 1910 and at this time, June, 1911, 
almost the whole of a fifteen-acre orchard has been destroyed. 
Case No. 24. —This is a very interesting occurrence. The land 
was sown to sorghum in the summer of 1910, but the crop was a 
complete failure. There is a large irrigating ditch running possibly 
six hundred feet to the north of it. The land is somewhat low but 
there is an orchard close by, in fact is immediatelv south and east 
