186 
Journal of Agricultural Research 
Vol. XXXI, No. 2 
ASH 
The average percentage composition and pounds to the acre of 
total ash in the corn kernel grown with varying quantities of irrigation 
water and manure are given in Table III. 
The com kernel grown with 40 inches of irrigation water contains 
8 per cent more ash than the com kernel grown with no irrigation 
water, but the ash is as high with 10 inches of water as with 40. The 
ash content is highest where the soil receives enough moisture to 
promote maximum bacterial activity with the resulting liberation 
of the maximum of plant food. 
Table III .—Percentages and pounds per acre of total ash in the corn kernel grown 
with varying quantities of irrigation water and manure 
Treatment 
Ash 
Nitrogen 
per acre 
Treatment 
Ash 
Nitrogen 
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 
1.65 
1.66 
1.79 
1.78 
1.76 
Pounds 
62.46 
74.05 
75.39 
81.73 
81.39 
40 inches irrigation water 1 _ 
No manure 2 .__ 
5 tons manure 2 . 
15 tons manure 2 .. 
Per cent 
1.79 
1.65 
1.75 
1.76 
Pounds 
76.79 
58.96 
82.20 
84.74 
i And varying quantities of manure. 2 And varying quantities of irrigation water. 
That it is the available plant food which determines the ash con¬ 
tent of the grain is well brought out by the results with the manurial 
treatments. The grain grown on soil receiving 5 tons of manure per 
acre yearly contains 6 per cent more ash than corn grown under 
similar conditions but receiving no manure. That grown on soil 
receiving 15 tons of manure yearly contains only slightly more ash 
than that grown with 5 tons of manure. 
The quality of ash in the corn kernel removed from the soil increases 
as the water applied increases up to 20 inches; above this there is a 
decrease. That removed by the plant markedly increases with 
increase in manure. 
PHOSPHORUS 
The phosphorus content of the corn kernel increased progressively 
with the irrigation water applied (Table IV). The kernel of copiously 
irrigated corn contained more than 9 per cent more phosphorus than 
did that of the unirrigated. The percentage might have been still 
higher if greater quantities of water had been applied (5). Unirri¬ 
gated corn has been found to be higher in phosphorus than unirrigated 
wheat, oats, or barley. However, irrigated wheat, oats, and barley 
were higher in phosphorus than the highly irrigated corn. The 
increase due to the use of manure is very small. 
With one exception the quantity of phosphorus removed from the 
soil by the corn grain increased as the water applied increased up to 
30 inches. The quantity removed from the manured plats increased 
as the manure applied increased. The increase due to manure was 
greater than the increase due to water. The lowest phosphorus 
content of the corn kernel, as grown on this soil, is 29 per cent higher 
than the average reported by Hopkins (£, p. 60S) after von Wolff; 
the highest is 42 per cent higher than the average of von Wolff. 
These results and those previously published (5) make it certain that 
