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

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