Economic and Marketing Information                                                                                                                                                                                          FOR INDIANA  FARMERS
Prepared by the Agricultural Staff of Purdue University, Lafayette, Indiana      
June  30,   1961
by JOHN  E.  KADLEC and   LA VON  SMITH,  Agricultural  Economics,  and   DAN  WIERSMA,  Agronomy
Can you make more money by using sprinkler
irrigation? Here are some factors you need to consider before deciding whether or not irrigation will
be profitable for you.
Returns to  Irrigation
Increased Yield usually accounts for the greatest
return to irrigation. Sandy soils, because of their
low moisture holding capacity, are likely to give
the greatest yield response to irrigation. Recent
research on Fox sandy loam soil in Sullivan County, Indiana, indicates yield response of corn to water,
nitrogen and seeding rate as shown in Table 1.
Since water can come from rainfall as well as irrigation, it is important to consider the rainfall quantity and distribution. Table 1 also shows the chances
of receiving various amounts of rainfall from June
20 to September 6, based on rainfall records of the
area. Similar records are available for most parts
of the Midwest.
Additional dollar returns to irrigation depend on
the value of increased yields. High value crops such
as corn and specialty crops are likely to give higher
returns to irrigation than lower value crops.
Improved Quality is another factor that contributes to higher returns. Irrigating vegetables frequently increases returns as a result of improving
quality and making a higher percentage of the crops
marketable. Irrigation may also increase returns
when used to prevent frost damage to such crops as
strawberries and fruits.
Quality in field crops is not often measured, but
research has shown that more minerals are taken up
by plants that have adequate moisture. And, corn
not subjected to drouth is usually better filled and
thus of higher quality.
Intensified Livestock Operations are possible with
irrigation. With proper management the seasonal
carrying capacity of pastures and grain crop yields
can be substantially increased. Also, irrigation eliminates wide fluctuations in available feed caused by
year to year variations in rainfall.
Double-cropping systems are another method of
intensification. Vegetables or winter wheat are harvested early in the season permitting a second crop,
either a forage or a short season crop such as soybeans. Double-cropping is usually most practical
with irrigation because an adequate moisture supply
for the second crop, particularly at germination
time, is insured.
Fertilization can be geared to plant needs without
regard to rainfall expectations. Because farmers who
irrigate fertilize on the basis of high soil moisture,
their yields are much higher even in extremely wet
years than the yields of farmers who do not irrigate.
Fertilization and irrigation complement each other
i.e., when both are used together the returns are
greater than the sum of the two used separately.
Irrigation also provides a means of applying fertilizer at any time. Fertilizer may be applied slowly
throughout the growing season in the irrigation
water. The returns to irrigation are influenced by
fertilization.
Table I. Years out of one-hundred that various
quantities of rainfall are expected and the corn
yields expected from these rainfall quantities on
Fox sandy  loam  soil,  Sullivan  County,  Indiana.
Estimated yield1
80 1b.
160 lb.
nitrogen
nitrogen
In. rainfall
Years out of
13,000
21,000
June   20
one-hundred
seeding
seeding
to September 6
expected
rate
rate
Inches
yr./100 yr.
bu.
bu.
0-4
6
16-
8-
4-6
16
46-
35-
6-8
23
75-
72-
8-10
22
101
103
10-12
15
1(1!)
nt;
12-14
9
112
123
14-16
4
112
128
over 16
5
108
129
weighted
average     8.78
84
85
'Assumes high levels of phosphate and potash and relatively  uniform  rainfall  distribution.
2Estimates—other yield data are based on experimental
plot data. Purdue Agricultural Experiment Station, Project
816.