IRBIGATION IN NORTHERN COLORADO. 
59 
is a nonretentive, very fine, sandy loam, underlain by coarse mate- 
rial which permits a very rapid drainage. This condition and the 
excellent water rights of the 
Greeley Canal No. 3 account for 
the very low duty of nearly 17 
acre- feet per acre for potatoes on 
the farm. Charles F. Mason on 
his farm near Greeley frequently 
practices a very rapid light irri- 
gation in alternate furrows and 
is enabled by this method to cover 
a very large acreage per day. In 
July, 1916, with a head of 3.75 
second-feet a field of 8.1 acres 
of beans was irrigated in 4} 
hours, or at the rate of 43 acres 
per day. High duties are in 
most cases accounted for by 
good irrigation practice, but in 
a few cases the cost of pump- 
ing, a scarcity of water, or a 
high ground-water table is re- 
sponsible. 
Dates of irrigations varied widely with conditions, such as type 
of soil, depth to water table, rainfall, date of planting, water supply, 
and others. The great- 
est range noted was a 
difference of 90 days 
between the earliest and 
latest first irrigation of 
alfalfa, the dates being 
April 17 and July 16. 
In Table 17 are given 
the average irrigation 
dates for the princi- 
pal crop in 1916, a 
5 
l 
4 
k 
8s 
if 

« 2 3 4 
YIELD IN TONS PER ACRE 
Fig. 10. — Irrigation of alfalfa. Relation 
between the depth of water applied 
and the yield. 
r. 
y / 
$J /, <g- 
W\a1 
10 20 30 40 50 60 70 
YIELD IN BUSHELS PER ACRE 
80 90 
Fig. 
normal year, which 
were obtained by giv-" 
ing the date of the be- 
ginning of the irrigation 
its proper number as a day of the year and then averaging these 
numbers 
11. — Irrigation of grain. Relation between 
the depth of water applied and the yield. 
