|
Table 9-2.
Effects of Irrigation on Alfalfa Hay Yield and Economics |
| |
Situation 1
(dry) |
Situation 2 (medium) |
Situation 3 (medium) |
Situation 4
(dry) |
Situation 5
(wet) |
|
Yield w/o
irrigation (tons/acre) |
2.40 |
5.00 |
5.00 |
3.00 |
6.67 |
|
Yield with
irrigation (tons/acre) |
10 |
8 |
12 |
6 |
6 |
|
Water needs
(inches/ton of hay) |
5 |
6 |
6 |
6 |
6 |
|
Water required
(inches) |
50 |
48 |
72 |
36 |
36 |
|
Effective rainfall
(inches) |
12 |
30 |
30 |
18 |
40 |
|
Irrigation required
(inches) |
38 |
18 |
42 |
18 |
-4 |
|
Irrigation required
(gallons/acre) |
1,031,791 |
488,743 |
1,140,400 |
488,743 |
-108,609 |
|
|
|
Pumping capacity
(gal/min) |
1000 |
800 |
450 |
800 |
450 |
|
Pumping
hours/acre/year |
17.20 |
10.18 |
42.24 |
10.18 |
-4.02 |
|
Field size (acres) |
120 |
120 |
120 |
120 |
120 |
|
|
|
Pumping cost
($/acre-inch) |
$7.50 |
$7.50 |
$7.50 |
$8.50 |
$8.50 |
|
Pumping cost
($/acre) |
$285.00 |
$135.00 |
$315.00 |
$153.00 |
-$34.00 |
|
|
|
Yield increase due
to irrigation |
7.6 |
3 |
7 |
3 |
-0.67 |
|
|
|
Selling price of
hay (dollars/ton) |
$90.00 |
$125.00 |
$125.00 |
$125.00 |
$125.00 |
|
Receipts (with
irrigation) ($/acre) |
$900.00 |
$1,000.00 |
$1,500.00 |
$750.00 |
$750.00 |
|
Receipts above
irrigation costs ($/acre) |
$615.00 |
$865.00 |
$1,185.00 |
$597.00 |
$784.00 |
|
Receipts w/o
irrigation ($/acre) |
$216.00 |
$625.00 |
$625.00 |
$375.00 |
$833.33 |
|
|
|
Other expenses
($/acre) for |
|
irrigated system ($35/acre), owned
equipment |
$350.00 |
$280.00 |
$420.00 |
$210.00 |
$210.00 |
|
irrigated system ($51/acre), custom
harvest |
$510.00 |
$408.00 |
$612.00 |
$306.00 |
$306.00 |
|
rainfed system ($45/acre), owned
equipment |
$108.00 |
$225.00 |
$225.00 |
$135.00 |
$300.00 |
|
rainfed system ($55/acre), custom
harvest |
$132.00 |
$275.00 |
$275.00 |
$165.00 |
$366.67 |
|
|
|
Returns above
specified costs for ($/acre) |
|
irrigated system
& owned equipment |
$265.00 |
$585.00 |
$765.00 |
$387.00 |
$574.00 |
|
irrigated system
& custom harvest |
$105.00 |
$457.00 |
$573.00 |
$291.00 |
$478.00 |
|
rainfed system &
owned equipment |
$108.00 |
$400.00 |
$400.00 |
$240.00 |
$533.33 |
|
rainfed system &
custom harvest |
$84.00 |
$350.00 |
$350.00 |
$210.00 |
$466.67 |
Back to Irrigation
|
Table 9-3. Sources of
information, assumptions, and calculations related to the
economics of irrigating alfalfa |
|
Information provided by producer |
Comments and Normal Ranges |
|
|
|
Yield with irrigation (tons/acre) |
5 to 10 tons/acre |
|
Water needs (inches/ton of hay) |
5 to 6 inches/ton |
|
Effective rainfall (inches) |
Includes rainfall, minus-runoff, plus run-on,
plus water available from subirrigation |
|
Pumping capacity (gal/min) |
300 to 1200 gpm |
|
Field size (acres) |
|
|
Pumping cost ($/acre-inch) |
Varies with energy source, pumping depth,
irrigation system type. Sprinkler system powered with electricity
($5 to $6/ acre-inch). Sprinkler system powered with natural gas
($6 to $9/acre-inch). |
| |
|
Assumptions |
These expenses range normally from $30 to $60
Under special situations the range may be wider. |
|
Other expenses in irrigated system
($35/acre), owned equipment |
includes prorated establishment costs,
insecticide, herbicide, fertilizer, operating capital, machinery
labor, machinery, fuel, lube, repairs, interest, depreciation,
taxes, insurance, etc. |
|
Other expenses in irrigated system
($51/acre), custom harvest |
same as above plus swathing, baling, hauling |
|
Other expenses in rainfed system
($45/acre), owned equipment |
includes prorated establishment costs,
insecticide, herbicide, fertilizer, operating capital, machinery
labor, machinery, fuel, lube, repairs, interest, depreciation,
taxes, insurance, etc. |
|
Other expenses in rainfed system
($55/acre), custom harvest |
same as above plus swathing, baling, hauling |
| |
|
Calculated Values |
Based on |
|
Water required (inches) |
yield X in of water/ton of hay |
|
Irrigation required (inches) |
required less rainfall |
|
Irrigation required (gallons/acre) |
7.48 gal/cubic ft |
|
Pumping hours/acre/year |
gal required/capacity/60 minutes/hr |
|
Pumping cost ($/acre) |
inches required X $/acre-inch |
|
Yield w/o irrigation (tons/acre) |
effective rainfall/inches/ton |
|
Receipts (with irrigation) ($/acre) |
gross income |
|
Receipts above irrigation costs ($/acre) |
less cost for irrigation |
|
Receipts w/o irrigation ($/acre) |
gross income |
Back to Irrigation
|