1104 
Journal of Agricultural Research 
Vol. XXXI, No. 12 
One plot in each of the two series was covered to one of the follow¬ 
ing depths: 34 inch, % inch, 34 inch, % inch, % inch, and 1 inch. 
Clean sharp sand, dug from the sterile subsoil at Benton Flat, was 
used for covering. After the seed was sown and lightly pressed into 
the surface several toothpicks were inserted in each plot so that their 
points projected above the surface to a height exactly equal to the 
depth of cover desired. The sand was then put on and smoothed 
off level with the tops of the toothpicks. The lath partitions between 
plots prevented sand from washing from the plots with deep cover 
to those with shallower cover. 
For want of definite knowledge as to shading requirements, the bed 
was given one-half shade from the time of sowing to the end of the 
season. 
Water was applied to the bed by means of a hose and fine spray 
nozzle toward the close of each day during the dry period, except 
immediately after rains, in a moderate quantity sufficient to keep 
the upper soil lasers moist enough for good growth. 
Counts of germination and loss were made once a week, and a final 
survival count was made October 4, using the colored toothpick 
method. 
In the spring of 1914 the seedlings were removed for transplanting 
and 50 representative seedlings were mechanically selected for 
measurement by taking every third, fourth, or fifth plant, depending 
on the total number in the plot. Figures Were obtained on the 
following points: Length of root in inches, length of stem in inches, 
weight of 50 tops (fresh and surface dried) in grams. Typical speci¬ 
mens were pressed, and those in the broadcast series were photo¬ 
graphed, in February, 1917. 
The rest of the seedlings were transplanted at the Benton Flat 
nursery in the spring of 1914, using a standard “ Yale” board. Sur¬ 
vival records of transplants were obtained in the fall of 1915, together 
with measurements of the height and diameter at the ground line of 
every tenth plant. 
One bed sown at the Trapper Creek nursery on the Bitterroot 
National Forest May 27, 1914, contained 4 plots, each 1 by 4 feet, 
each plot containing about 600 seeds. One plot was covered to each 
of the following depths: 34 inch, % inch, 34 inch, and % inch. Seed 
was sown in drills 3 inches apart, 4 drills per plot, lengthwise. Counts 
of germination and survival were made June 15, July 1, 15, and 22, 
and again October 1. Owing to the conditions at Trapper Creek, it 
was not possible to control this experiment as carefully or have as 
complete records as for the 1913 experiment at Priest River. The 
value of this experiment lies chiefly m confirming, in a general way, 
the Priest River results, and in throwing an interesting sidelight upon 
the effect of different climatic conditions and methods of irrigation 
on the optimum depth of cover for yellow pine. 
DATA 
The germination figures obtained in the 1913 series at the three 
nurseries—Priest River, Savenac, and Boulder—are summarized in 
Table I. 
