946 
Journal of Agricultural Research voi. xxiv, No.« 
OF IRRIGATION WAT^R ON WEIGHT OF KERNEL AND VARIATION OF NITROGEN 
DURING GROWTH 
It is generally believed that the final filling of the kernel takes place 
some time immediately after the grain has been cut. This belief has 
been based almost entirely on theory, and there is nothing in literature 
of a scientific nature that informs us as to its correctness. The impor¬ 
tance of water in assisting the transference of the nitrogen into the grain 
has been studied, so that we are aware of the influence of water in increas¬ 
ing the weight and nitrogen content of the grain in the early stages of 
kernel development. 
The plan for the first year of the experiment was to study the nitrogen 
composition of the developing grain at intervals of one week. The land 
was divided into five different plots as follows: Plot I, receiving rainfall 
amounting to approximately 8.78 inches; plot II, irrigated sufficiently to 
make the total rain and irrigation water equal to 15 inches; plot III, 
given 20 inches of water; plot IV, given 25 inches of water; and plot V, 
given 30 inches of water. Blocks of entire plants were pulled at each 
period and stored. Afterwards the grain was threshed out and analyzed. 
The results for average weight of kernels are recorded in Table VI, and 
average results for percentage of nitrogen are recorded in Table VII. 
Table VI .—Weight of grain grown with various amounts of water 
Date. 
Plot I, 
rainfall 
only. 
Plot II, 
15 inches 
of water. 
Plot III, 
20 inches 
of water. 
Plot IV, 
25 inches 
of water. 
Plot V, 
30 inches 
of water. 
Gm. 
Gtn. 
Gw. 
Gw. 
Gw. 
July I. 
0. 0069 
0. 0052 
0. 0061 
0. 0051 
0. 0064 
8. 
. 0151 
. 0148 
.0144 
.0136 
. 0117 
IS . 
, 0262 
.0263 
. 0262 
. 0238 
.0230 
22. 
.0322 
■ 033s 
•037s 
•0347 
- 0346 
29 .. 
•0333 
• 0356 
.0407 
•0379 
.0398 
Table VII .—Nitrogen in grain grown with various amounts of water 
Date. 
Plot I, 
rainfall 
only. 
Plot II, 
IS inches 
of water. 
Plot III, 
20 inches 
of water. 
Plot IV, 
25 inches 
of water. 
Plot V, 
30 inches 
of water. 
Tulv I.. 
Per cent. 
3.00 
2. S 3 
2. 42 
2. s6 
2 - 73 
Per cent. 
3. 21 
2. 38 
2. 29 
2.31 
2. 20 
Per cent. 
3-04 
2. 21 
1. 82 
2. 07 
2. 14 
Per cent. 
2.9s 
I- 9 S 
I. 92 
I. 97 
I. 92 
Per cent. 
2. 63 
2. 60 
1. 97 
2. 04 
2. 02 
8. 
TC. 
^0 .*. 
22 ... .. 
. 
The highest average weight of the kernels for the first two weeks of 
development was obtained in the nonirrigated plot I. At the end of the 
third week the weight of the kernels were equally as high in plots II and 
III as in plot I. For the fourth week period and at maturity, the weight 
of the kernels in plots II, III, IV, and V exceeded those of plot I. 
With reference to nitrogen content for the first week, plots I, II, and 
IV have about the same values. Wheat from plot II tested the highest 
and wheat from plot V analyzed the lowest for nitrogen content. In the 
