30 
tinue, the area now " reclaimed " but not used will supply the demand 
for new land of this kind for a much longer period than is indicated 
above. 
No doubt the very marked decline in the rate of increase in acre- 
age irrigated during the few years just passed is due in part to the 
general depression in agriculture that not only has checked expan- 
sion, but has brought about demands for reduction in acreage in 
crops in this country. So long as the depression lasts, there is no 
reason to expect a revival in the demand for reclaimed land. How- 
ever, the depression has merely intensified a tendency already ex- 
isting. The census figures indicate that the rate of increase began 
declining long before the recent depression, while the Eeclamation 
Service figures show an increasingly rapid decline during the boom 
years from 1916 to 1921. 
The probable explanation of the long-time decline is the increas- 
ing cost of reclamation work. The report of the fourteenth census 
shows the average cost per acre for irrigation works to have been 
as shown in Table 15 for the census years for which this item has 
been reported. 
Table 15. — Average cost per acre for irrigation works. 
Year. 
Cost. 
Percentage 
of increase 
over the 
preceding 
census 
year. 
Percentage 
of increase 
over 
average 
for 1890. 
1890 
1900 
1910 
1920 
$7.96 
9.04 
15.85 
26.81 
13.6 
75.3 
69.1 
13.6 
99.1 
236.8 
The figures given in Table 15 do not correctly represent the in- 
creased cost of new construction because the data on which each 
average is based includes the data on which the preceding averages 
are based. The correct showing for increased cost is obtained by 
making averages based on increased acreage and increased cost. 
Averages made in this way are given in Table 16. 
Table 16. — Average cost per acre for ii^rigation of land brought under irriga- 
tion in each decade covered by the census. 
Year. 
Area on which average is 
based. 
Cost on which average is 
based. 
Average cost per acre. 
Acres. 
Increase over 
preceding 
area. 
Amount. 
Increase over 
preceding 
amount. 
Cost per 
acre for 
increased 
area. 
Per cent of 
increase 
over 
preceding 
decade. 
Per cent 
increase 
over 1890. 
1890 
1900 
1910 
1920 
3, 715, 758 
7, 744, 467 
20, 285, 403 
26, 020, 477 
$29, 533, 921 
70, 010, 594 
321,454,008 
697, 657, 328 
i $7. 95 
10. 05 
20.05 
65.60 
4, 028, 709 
12, .540, 936 
5, 735, 074 
.•?}(), 17ii, 673 
251,443,414 
376, 203, 320 
26. 4 
99.7 
226.7 
26.4 
152. 2 
725.2 
Average for all land irrigated to 1890, 
