Purdue University Mimeo AE-27a
Agricultural Extension Service Rev. March 1954(1M)
SPRINKLER IRRIGATION
20 QUESTIONS AND ANSWERS
Donald R. Sisson
Extension Agricultural Engineer
and
Gerald G. Williams
Agronomy Department
1. WHY IS IRRIGATION USED IN INDIANA?
Irrigation can increase crop production by providing water supple^
mental to rainfall during periods of minor and major drought. Irrigation is of greatest value during years of less than normal or poorly distributed rainfall.  The following table indicates the average
number of different drought peroids occuring per year.
-"-DROUGHT PERIODS IN INDIANA
(Average for 45 year period)
Duration of Drought Average number of
Drought Periods per year
During Growing Season
11 days or longer 4.0
16 days or longer 2.0
21 days or longer 1.0
26 days or longer 0.5
31 days or longer 0.3
36 days or longer 0.2
41 days or longer Oil
-^Drought is defined as a period in which less than 1/4 inch of rainfall occurs in any 24 hour period.
2. WHAT CROPS CAN BE SUCCESSFULLY IRRIGATED?
Corn, pasture and forage crops, fruits and vegetables have been
some of the principal crops irrigated successfully in Indiana. Corn
irrigation has been very successful on sandy soils.  Three years of
Purdue experiments on Plainfield sand have shown an average yield
of 134 bushels on irrigated plots compared to 50 bushels on nonirri-
gated.  The maximum yield for irrigated corn was 144 bushels per
acre
Farmers have reported irrigation doubling and even tripling pasture carrying capacity.  Purdue Experiments on both sandy and loamy
soils have shown that irrigation can be expected to double forage
yields during many seasons.
It must be remembered good farm management is highly essential
for a farmer who plans to irrigate.Where fertility of the soil,poor
soil aeration, lack of insect control, or some other factor is limiting yields, irrigation alone cannot satisfactorily increase production.