6 The Colorado Experiment Station. 
formed in situ, but this is only a part of the purpose of the present 
bulletin. It is intended to extend the discussion of the occurrences 
of these nitre spots and to describe further the effects of this nitre 
on the soil and plants. In a subsequent bulletin I intend to take up, 
in some degree of fullness, its effect upon the growth and quality of 
the sugar beet, more especially upon its composition. 
Case No. 5 —The orchards and localities described in Bul¬ 
letin 155 will not be treated of in this bulletin except as further 
observations made since Bulletin 155 was published may seem to 
justify, when they will be referred to by the number under which 
they were described in that bulletin. We will continue the numbers 
beginning with orchard or case No. 5. I visited this orchard, quite 
a large one, on the 12th of June, 1909. I did not obtain the age 
of the trees but they were probably not less than 15 years old. 
They had been sprayed heavily, especially in 1903, 1904 and 1905. 
There were a few trees in the orchard with corroded crowns, very 
probably due to arsenic, but arsenic had nothing to do with the 
trouble that we went to investigate. The condition of the orchard 
was, in the main, good; we, however, found twelve large trees in 
a group, with brown leaves and the trees appeared to be dead. The 
rest of the orchard was in good condition, the foliage was of full 
size and healthy in color. We learned from the owner that these 
trees had appeared perfectly healthy until within a fortnight or 
less. The orchard had not been irrigated as I inferred from the 
appearance of the surface of the ground in parts of the orchard, 
but this was due to the overflow of a waste ditch some weeks 
previous to this time. The soil about these trees was mealy on 
the surface and felt soft under the foot. We dug a hole near to 
one of these dead trees, five and a half feet deep. The soil was 
moist but there was no free water at this depth. I took a sample of 
soil from a place near to one of the very badly affected trees to a 
depth of one foot. The water-soluble in this sample amounted to 
0.57 percent. It was rich in nitric acid but owing to the small 
amount of residue at our disposal no analysis of it was attempted. 
It was evident that these trees were not drowned by the rising 
of ground water nor killed by an excessive amount of ordinary 
alkali. I next visited this orchard on September 21, 1909. More 
trees were affected and there was no improvement in the condition 
of any trees previously observed. On November 3 I again 
visited it and dug a hole five and a half feet deep near a tree which 
was dying. The soil was wet but there was no free water, and 
this was at the season when the fall irrigation of adjoining lands 
was being applied. A sample of soil was taken from the surface 
of this ground to a depth of two inches. The surface was slightly 
incrusted and mealy underneath but there was no efflorescence. In 
places the surface appeared wet, evidently due to the presence of 
