Crop Irrigation Feed Conversion Calculator

The Crop Irrigation Feed Conversion Calculator expresses irrigation input relative to harvested crop output. Because the source title uses “feed conversion” in a crop-irrigation context, this implementation treats the supplied irrigation water as the production input and reports how many gallons of irrigation were applied per pound of harvested crop, along with the inverse crop output per 1,000 gallons.

This ratio is useful for comparing water-use performance across comparable fields, crop cycles, or management scenarios when both applied irrigation and harvested mass are known. It is not an animal feed-conversion ratio and should not be compared with livestock FCR values. Crop quality, marketable yield, rainfall, soil-water contribution, salinity management, and differences in growing period can materially affect interpretation, so comparisons should use a consistent boundary and crop basis.

Irrigation conversion inputs

Irrigation water applied

gal

Harvested crop weight

Marketable share of harvest

Result

—

gallons of irrigation per marketable pound

Marketable harvest weight—

Marketable lb per 1,000 gal—

Gallons per total harvested lb—

How to use

1. Enter irrigation water applied
Use metered or estimated irrigation volume for the same crop area and production period as the harvest data.

2. Enter harvested crop weight
Use total harvested mass before the optional marketable adjustment.

3. Set the marketable share
Enter the percentage of harvested weight that qualifies as marketable output; use 100% if no adjustment is needed.

4. Review the conversion ratio
The main result shows irrigation gallons per marketable pound, so lower values indicate less applied irrigation per unit of marketable crop under the same boundary.

5. Use the inverse metric for comparison
Pounds per 1,000 gallons can be easier to compare when higher output per water input is preferred.

Formula

Marketable harvest = Total harvest × Marketable share Irrigation conversion ratio = Irrigation gallons ÷ Marketable harvest pounds Marketable yield per 1,000 gallons = Marketable harvest ÷ Irrigation gallons × 1,000

This page interprets “feed conversion” as an input-to-output conversion ratio for crop irrigation. It does not estimate crop biological water productivity from evapotranspiration and it does not include rainfall unless rainfall is already incorporated in the chosen water-input boundary.

What the result means

The main result tells you how many gallons of applied irrigation correspond to one pound of marketable harvested crop. Lower gallons per pound indicate less applied irrigation per unit of output, when comparing like-for-like production systems.

For meaningful benchmarking, use the same crop, product moisture basis, growing period, harvested-area boundary, and treatment of rainfall or stored soil water.

Example calculation

Given: A crop block receives 325,000 gallons of irrigation and produces 18,000 pounds of harvest, of which 92% is marketable.

Calculation: Marketable harvest = 18,000 × 0.92 = 16,560 lb. Irrigation conversion ratio = 325,000 ÷ 16,560 = 19.63 gal/lb. Marketable yield per 1,000 gallons = 16,560 ÷ 325,000 × 1,000 = 50.95 lb.

Result: 19.63 gallons of irrigation per marketable pound.

Interpretation: Under this accounting boundary, every marketable pound corresponds to about 19.6 gallons of applied irrigation.

FAQ

Is this an animal feed conversion ratio?

No. In this crop-irrigation implementation, the ratio compares irrigation-water input with crop output because the source tool title combines irrigation and feed conversion.

Should rainfall be included in irrigation water applied?

Normally, enter only the irrigation volume if you want an irrigation-input ratio. If you want total water input, define that broader boundary consistently for every comparison.

Why adjust for marketable share?

A field can produce harvested biomass that is not saleable. Using marketable output can better match commercial water-use comparisons when quality losses matter.

Can I compare two different crops?

You can calculate both, but direct comparison can be misleading because crop composition, moisture content, growing duration, and production value differ.

How is this different from the Water Needs Estimator?

The Water Needs Estimator predicts a required irrigation volume from evapotranspiration and efficiency. This calculator starts with actual or assumed water applied and compares it with harvested output.

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