July 15,1925 Influence of Irrigation Water and Manure on Com 
187 
grains grown on this soil are exceptionally rich in phosphorus and 
that the phosphorus content of grain is increased by irrigation water, 
the increase being due primarily to a greater supply of available 
phosphorus. 
Table IV .—Percentages and pounds per acre of total phosphorus in the corn kernel 
grown with varying quantities of irrigation water and manure 
Treatment 
Phos¬ 
phorus 
Phos¬ 
phorus 
per acre 
Treatment 
Phos¬ 
phorus 
Phos¬ 
phorus 
per acre 
No irrigation water 1 . 
6 inches irrigation water 1 . 
10 inches irrigation water 1 _ 
20 inches irrigation water 1 _ 
30 inches irrigation water 1 _ 
Per cent 
0.32 
.33 
.33 
.33 
.35 
Pounds 
12.12 
14.50 
13.69 
15.95 
16.13 
40 inches irrigation water L... 
No manure 2 . 
5 tons manure 2 . 
15 tons manure 2 . 
Per cent 
.35 
.33 
.34 
.33 
Pounds 
15.54 
11.84 
16.02 
16.11 
* And varying quantities of manure. 2 And varying quantities of irrigation water. 
CALCIUM 
The calcium content of the same grain is given in Table V. 
Table V .—Percentages and pounds per acre of calcium in the corn kernel grown 
with varying quantities of irrigation water and manure 
Treatment 
Calcium 
Calcium 
per acre 
Treatment 
Calcium 
Calcium 
per acre 
No irrigation water 1 .— 
5 inches irrigation water 1 . 
10 inches irrigation water 1 .... 
20 inches irrigation water 1 _ 
30 inches irrigation water 1 _ 
Per cent 
0.13 
.18 
.18 
.14 
.14 
Pounds 
4.77 
8.08 
7.01 
6.89 
5.31 
40 inches irrigation water *_ 
No manure* 2 ---. 
5 tons manure 2 . 
15 tons manure 2 .. 
Per cent 
0.14 
.14 
.15 
.15 
Pounds 
6.09 
4.81 
6.12 
8.15 
1 And varying quantities of manure. 2 And varying quantities of irrigation water. 
The percentage of calcium in the corn kernel increases with the 
irrigation water applied up to 10 inches yearly; above this it gradually 
decreases. Corn grown with 10 inches of irrigation water contains 
40 per cent more calcium than corn grown without irrigation water; 
that receiving 40 inches of irrigation water contains only 8 per cent 
more calcium. Manure also increases the calcium content of the corn, 
but not to the same extent as does irrigation. 
The calcium-low corn in this series contains about six times the 
quantity reported by Hopkins (£, p. 603), whereas the calcium-rich 
corn contains nearly nine times the amount. Differences such as this 
must be of great significance in animal nutrition. Moreover, the 
calcium-phosphorus ratio changes with the application of irrigation 
water. In the corn grown with irrigation water the calcium- 
phosphorus ratio is 1:2.5, that grown with 10 inches of irrigation 
water is 1: 1.8, whereas that grown with 40 inches has a ratio of 
1:2.6. The application of manure also narrows the calcium- 
phosphorus ratio. It appears from these results, viewed from the 
standpoint of the mineral elements, that corn grown on this soil with 
10 inches of irrigation water is the most valuable from the viewpoint of 
the nutrition of animals. 
