14 
Colorado Experiment Station 
We took no samples for the determinations of moisture and 
nitric nitrogen in January because the weather Avas unfavorable 
and the ground f.rozen. We took only two series of samples in 
February, i.e. on the IGtii of the month when Ave found the ground 
frozen to a depth of six inches. A comparison of the results ob¬ 
tained for the samples taken 13 December, 1915, Avith those obtained 
for the same section in February and again in March,1916, shoAvs 
that the distribution of the nitric nitrogen had changed during the 
interval betAveen 13 December, 1915 and 16 February, 1916, but 
had remained essentiallv the same from 16 Februaiw to 22 March, 
*/ 
1916. These differences in the distribution are most marked in the 
thij*d and fourth foot. Concerning the total amount present in the 
soil, there is in every case less in the second, third and fourth foot, 
in the tAvo last series of sami)les taken, than in those taken 13 De¬ 
cember, 1915, but more than in those taken 22 November, 1915. The 
surface foot shoAvs an increase but it is not sufficient to balance the 
loss in the bottom three feet. 
COXCEILMXG THE J)ISTRIBUTIOX OF MOISTURE 
Tile rainfall in 1913 Avas only 6.77 inches during the groAving 
season and this fell during tAvo periods, the first from 9 to 20 May 
and the second from 13 to 23 July, Avith almost no cloudy Aveather. 
In 1915 Ave had 13.47 inches rainfall distributed rather evenly 
throughout the corresponding period. In July, Ave had only 2.12 
inches rainfall, but this Avas distributed over eleven days and a 
‘'trace” is recorded on five days. Only eleven days during the 
month are recorded as clear. In 1913, Ave had a greater rainfall 
during this month, but its distribution Avas different and the cloudi¬ 
ness was very much less; there Avas only one day designated as 
AA^holly cloudy. The moisture in the soil, as shoAvn by our samples, 
Avas much more clearly alike during the tAvo seasons than one 
Avould expect, taking the very different Aveather conditions into con¬ 
sideration. But it must be remembered that we alloAved a few days 
to elapse after a rain before we took our soil samples. These sam¬ 
ples, except those designated fallow, Avere taken from cropped land. 
Determinations of moisture in the surface samples immediately after 
a rain Avould have had no object AvhateAuu’ for our purposes. A 
comparison of the tables given for 1913, in Part 1 (Bulletin 208), 
Avith those giAmn for 1915 in the preceding pages, Avill shoAV no reg¬ 
ularity in the differences, which are much less than Ave Avould ex¬ 
pect, tAvo percent being about the maximum. 
1 deem it almost useless to state that the time of the rainfall, 
the cloudiness and temperature are much more important than the 
amount of the rainfall. Every farmer in the extreme eastern states 
is aAvare of this, for a feAV Avarm, foggy days Avith no rainfall may 
ruin the most flattering prospects for a AAdieat crop. Warm, cloudy 
Aveather, Avith but little AAund and enough rain to keep the plants Avet 
