1. Are Your Soils Irrigable?
You must check the county soil survey to determine the irrigation suitability of the
soils in the fields you want to irrigate. If your county soil survey hasn't been printed,
the local Soil Conservation Service (SCS) office can obtain the information for you. Not
all soils can be irrigated due to various physical problems, such as low infiltration
rates and poor internal drainage which may cause salt buildup. Soils are classified as
either irrigable, conditional or non-irrigable and are defined in the following way:
Irrigable soils have no restrictions for sustained irrigation using proper
application rates, amounts and water quality.
Conditional soils have restrictions for sustained successful irrigation due to
such factors as water table elevation, layers of low permeability, potential for
salinization, steep slopes and other problems. Some restrictions can be corrected with
drainage. Conditional soils should have a detailed field level soil survey conducted
before irrigation is developed.
Non-irrigable soils have severe restrictions to irrigation and should only be
developed where they are minor inclusions into irrigable soils.
Sources of Information:
Extension Service, SCS, County Soil Survey, North Dakota Irrigation Guide, On-Site
Investigations.
2. Can You Obtain the Quantity and Quality of Water You Need?
The water supply is the heart of any irrigation development. If you are going to use a
surface water source, check with the SCS or State Water Commission to determine if there
will be sufficient water available during the summer months. If you are going to use
ground water, check the county ground water survey published by the State Water
Commission. It will provide approximate information as to location, size and production
capacity of the aquifers within your county.
Small aquifers may exist that are not shown in the county ground water survey. Test
drilling and pumping is the only sure way to determine if sufficient water is available.
The minimum amount needed is 6 gallons per minute per irrigated acre. A state certified
irrigation well driller should drill the test holes. If there is sufficient water, one or
two of the test holes should be developed as observation wells to monitor the effect of
irrigation pumping on the ground water level and assist in diagnosis of well problems
should they occur.
Both ground water and surface water should be tested for quality. Water samples sent to
the NDSU Soil Testing Laboratory along with the soil survey information will be analyzed
for quality and correlated with the soil conditions on your farm. This is very important
because the soil type will determine the quality of water which can be used.
A water permit is required for all water appropriations except domestic use and
non-commercial lawn and garden irrigation of one acre or less. When a water permit is
first issued it is called a conditional permit. When the water source is developed and the
irrigation system has been installed and inspected by the State Water Commission, the
conditional permit is changed to a perfected permit.
A water permit should be obtained before a production well is drilled and irrigation
systems are constructed. A water permit application and instructions can be obtained from
the State Water Commission. When submitted to the State Water Commission, the application
must be accompanied by the appropriate fee and a map showing the location of the water
diversion, acreage to be irrigated and a signed certificate of surveyor. You can fill out
the permit application with the help of a local surveyor, the SCS, or a consulting
engineer.
Sources of Information:
Extension Service, NDSU Soil Testing Lab, SCS, State Water Commission, County Ground Water
Survey, Test Drilling, Licensed Well Drillers.
3. What Kind of Power and Equipment Will You Need?
Power Source
If available, electricity is generally the preferred source of power. However, it may be
economically advantageous to use an internal combustion engine if your land is not near an
existing power line. Construction costs and repayment for extension of power lines vary
with each electrical provider. An estimation of annual power use, costs and construction
repayment is necessary to determine the most economical power source.
If electricity will be used, three-phase power is preferred, but phase converters allow
single-phase power use. Early contact with the power supplier is necessary to allow time
to plan and construct facilities.
Equipment
Select an irrigation system (pump, motor, pipeline, water application equipment) which
fits your needs relative to water supply, irrigated acreage, crops to be grown, crop
rotations, labor requirements and the power supply. Irrigation system pressure
requirements and sprinkler selection should be based on soil and topography. Remember,
this equipment will have a useful life of 15 to 20 years or more and selecting the wrong
system may limit future cropping patterns.
Visit irrigators with similar systems and listen to their experiences and opinions to
determine the advantages and disadvantages of their systems. Select a dealer who is well
established, is capable of designing a good system and has a good service record. Buy as
much as possible of the entire system from one dealer. This may help eliminate problems of
responsibility and installation.
The pump and motor should be adequately sized to fit the system and the well or water
supply. The pipe size and wall thickness should be selected to match flow rate and
pressure requirements. Pump and motor information should be furnished by the dealer and
filed for future reference. Typical equipment costs are shown on the last page.
Sources of Information:
Extension Service, SCS, Electric Power Suppliers, Other Irrigators, Licensed Well
Drillers, Irrigation Dealers, Contractors.
4. Does Irrigation Pay in Your Farm Enterprise?
Detailed crop budgets covering economic and cash costs must be prepared for the
proposed irrigated cropping system. If the budgets show an adequate return to labor,
capital and management, then a total enterprise analysis should be made to determine how
irrigation will fit into the farming operation. For example, irrigation of grass or hay
may not bring a big return by itself, but coupled with a livestock operation may increase
net returns and lend stability to the farm enterprise. Irrigation alone does not assure
financial success. It requires planning and good management on the part of the farm
operator. Without these two key ingredients, failure is almost assured.
Sources of Information:
Extension Service.
5. Can You Obtain Financing?
The problem of adequate financing can be minimized by proper planning prior to
contacting a financial institution. Success in irrigation depends largely on your
management ability. An indication of that ability can be expressed to your credit supplier
in the form of farm records, profit and loss statements, net worth statements, and cash
flow statements. In addition to these records, you should be prepared to supply your
credit agency with an estimation of the potential payback capacity of the irrigation
investment. This is where the crop budgets and total enterprise analysis in step 4 would
be very helpful.
Sources of Information:
Irrigation Equipment Manufacturers and Dealers, Banks, Farm Financial Organizations
6. How Are You Going to Select and Manage Your Irrigated Crops?
Crops selected to be irrigated must exhibit an economic yield increase to irrigation.
This means the average yearly yield increase over dryland production must be great enough
to pay for the investment in irrigation and increased production costs as well as some
additional profit. Historically, irrigating corn (for silage or grain), alfalfa,
sugarbeets, potatoes, and dry edible beans has been profitable for good irrigation
managers.
Irrigation provides an environment conducive to increased plant production for long
season crops. However, it also provides a favorable environment for disease, insects and
weeds. The irrigator must know how to manage the irrigation system and crop rotations to
minimize potential problems. By scouting the field on a regular basis and using Integrated
Pest Management methods and Best Management Practices the irrigator should be able to
manage the irrigation system profitably. The irrigator must be aware of agronomic
practices that favor irrigation and are crop specific, such as proper row widths,
appropriate plant populations, higher fertilizer requirements, split applications of
fertilizer to minimize leaching potential and hybrid selection.
Irrigated crop water management is extremely important to prevent yield loss due to
moisture stress, minimize pumping costs and prevent leaching of nutrients. A method of
irrigation scheduling must be used. Soil moisture monitoring by the feel method is
commonly used, but there are more accurate methods such as the checkbook method. Whichever
method is used, it will require increased management skills and additional time.
Irrigation scheduling is a daily process.
Sources of Information:
Extension Service, SCS, NDSU Experiment Station.
Irrigation Equipment Costs
The following example development costs are for a center pivot irrigation system
covering 130 acres. One well is assumed to provide an adequate water supply of 800 gallons
per minute for the system.
- Irrigation System: $33,000 to $40,000 for a new, full quarter section, center
pivot system. Included is a chemigation check valve, flowmeter, gate valve, pressure gage,
air and pressure relief valves and a chemigation pump with a storage tank.
- Pipeline: A pipeline from the well to the pivot should be either 8 or 10 inches
in diameter to reduce friction loss and provide sufficient carrying capacity. Air and
pressure relief valves as well as a pump out must be part of the piping system. Pipe cost
can vary significantly, so check with local supplier.
- Power and Control: An electric safety circuit must be connected between the well
and the pivot control panel. This provides protection in case of pivot or pump failure.
a) Electric drive pivot -- electrical lines must be run from the local electric supplier
to the control panel and then to the pivot. Three phase power is preferable if
economically available. An engine and generator can also supply power.
b) Hydraulic drive pivot _ either electric or engine driven hydraulic pump is required.
- Well Costs: $12,000 to $18,000. Includes test holes, production well site
selection, drilling, testing and developing, screen and casing. Typical costs range from
$125 to $175 per foot completed.
- Pump and Motor: Costs depend on the depth to water, feet of lift, system pressure
requirements, length of pipeline, and flow rate. Electric powered pump may be about
$14,000, a comparable diesel powered pump may cost about $17,000 which includes the right
angle gear head, fuel tank, and other accoutrements.
Total capital costs are calculated using an annual straight line depreciation and a
zero salvage. The following example calculates the yearly total capital cost of a typical
irrigation system on a per acre basis:
---------------------------------------------------------------
Est. Depreciation
New Cost Life (per acre/yr.)
---------------------------------------------------------------
Irrigation System $35,000 15 yrs $17.95
Pipeline & Wire $10,000 20 yrs $3.85
Deep Well $16,000 20 yrs $6.15
Pump and Motor $14,000 15 yrs $7.18
------- -------
TOTAL $75,000 $35.13
---------------------------------------------------------------
Annual per Acre Interest on Average Investment is 10%.
$75,000
----------- x 0.10 = $28.85
(2) x (130)
TOTAL CAPITAL COST =
Depreciation plus Interest = $35.13 + $28.85 = $63.98/acre/year
AE-92, December 1993
