Dec. 15,1925 Mineral Composition of Sunflowers Crown for Silage 1197 . 
nitrates below this depth. Table IV shows the average loss of nitrate 
nitrogen for two plots at the time when the greatest loss shown in 
Figure 3 occurred. This, however, represents a loss of nitrate nitro¬ 
gen to a depth of 5 feet. Unpublished data of the writer show that 
there was no leaching of nitrates below the fifth foot for the years 
1911, 1912, 1913, and 1917. A slight leaching was noted in the years 
1914, 1915, and 1916. This leaching caused an increase in moisture 
of from 1 to 2 per cent in the fifth foot. It is hardly possible, how¬ 
ever, that this slight degree of leaching brought about the reduction 
apparent in Table IV. The table shows a gain in nitrate nitrogen 
between the first and second sampling for the year 1916. It must 
be noted, however, that on May 23, 1.35 parts per million of nitrate 
nitrogen was found in the soil, the smallest amount shown in the 
table. 
Table IV. — Loss or gain in parts per million of nitrate nitrogen in the soil to a 
depth of 5 feet . 
Year 
Plot No. 
Date of 
first 
sampling 
Parts per 
million of 
nitrate 
nitrogen 
Date of 
second 
sampling 
Parts per 
million of 
nitrate 
nitrogen 
Percent¬ 
age loss 
Loss in 
pounds 
per acre 
to a depth 
of 5 feet 
1911... 
13 and 16 
June 2 
5.00 
June 13 
2.68 
46.1 
19.0 
40.6 
21.9 
44.4 
49.3 
86.3 
°22.1 
19.6 
1912_ 
12 
June 3 
6.58 
June 12 
5.33 
1913___ 
13 and 16 
_do_ 
11.61 
July 1 
June 11 
9.07 
18.2 
31.2 
43.8 
+37.6 
14.1 
1914___ 
12 and 17 
May 21 
May 26 
May 23 
May 24 
7.68 
4.86 
1915_ __ 
13 and 16 
11.55 
June 9 
6.62 
1916__ 
12 and 17 
1.35 
___do. 
2. 61 
1917___ 
13 and 16 
6.61 
June 13 
5.49 
■ Gain. 
Note—T he percentages gain or loss of nitrate nitrogen given in this table were obtained by taking an 
average of the percentages of two plots; 17,500,000 pounds was the weight of the soil used in calculating the 
loss per acre. 
Meteorological data, not included ‘in this article, show that 0.97 
inch of precipitation fell as snow between May 9 and May 13. Be¬ 
tween May 19 and May 22 there was 1 inch of rain. This cold, wet 
spell was responsible for thd reduction of nitrates prior to the sam¬ 
pling on May 23, a fact which is clearly evident from unpublished 
data showing that on May 1 there had been 3.97 parts per million 
of nitrate nitrogen. This is one year when the reduction took place 
before the first date of sampling, shown in Table IV. 
If such conditions occur in soil receiving a monthly precipitation 
of something like 3 to 4 inches, it is reasonable to suppose that 
irrigation would have a decidedly greater influence in bringing about 
a loss of nitrogen either by carrying the nitrates into some porous 
substratum where they would be lost or, if there is no such substratum, 
to depths where denitrification would occur. It is altogether prob¬ 
able that irrigation favors even a greater reduction in the amount 
of available nitrogen than takes place under normal rainfall condi¬ 
tions. Hall ( 1) states that— 
a comparison Of the nitric nitrogen in the first 5 feet of a nonirrigated cultivated 
soil with that in an irrigated cultivated soil shows the nonirrigated soil of the 
same type to be much superior in nitrate content, although the irrigated soil 
does not get sufficient water to carry the nitrates to the fourth foot. 
78383—26f-7 
