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Common Units, Conversions, and Calculators for
Precision Agriculture Practitioners
The following list of units, equations, and calculators is provided to help practitioners of precision agriculture with data conversion, interpretation, and decision-making. If you have suggestions of other units, equations, or other useful calculators, please contact Dennis Hancock at dhancock@bae.uky.edu.
Commonly used units:
| Area | Length | Volume |
|
1 acre = 43,560 sq. ft = 0.405 ha 1 ha = 2.471 acres = 10,000 sq. m 1 sq. ft = 0.093 sq. m = 929 sq. cm 1 sq. m = 10.764 sq. ft |
1 in. = 2.54 cm 1 m = 3.281 ft 1 mile = 5280 ft = 1.609 km
|
1 ml = 1 cubic cm = 0.061 cubic in. 1 L = 0.264 gal 1 gal = 3.785 L = 231 cubic in. 1 bu = 35.239 L |
Liquid fertilizer weights:
| Fertilizer | lbs/gallon |
| 28-0-0 28% UAN | 10.67 |
| 32-0-0 32% UAN | 11.08 |
| 30-0-0 30% UAN | 10.86 |
| 10-34-0 Starter | 11.73 |
Equation for calculating yield in a given area:
 |
where: Y = yield (Bu/a, T/ha) m = mass flow rate (lbs/, kg/s) M = moisture content (%) s = cycle time (s) d = distance traveled (in, m) w = header width (in, m) ρ = Grain Density (lb/bu, kg/T) |
Common grain moisture at market and grain densities:
|
Grain |
Moisture Content (%) | Grain Density (lb/bu) |
| Corn | 15 | 56 |
| Soybeans | 13 | 60 |
| Wheat | 13.5 | 60 |
Easy to use, web-based calculators:
Seed Cost Calculator: When varying seeding rate, there are several characteristics that need to be considered: desired stand, row spacing, germination rate, purity, seeds per lb., etc. These characteristics must be compared between varieties and even within different lots of the same variety. The website was adapted by Sam McNeill (Ext. Specialist - BAE) from a spreadsheet tool originally developed by one of our KPAN members.
Calculating Fertilizer Application Rate: It is sometimes difficult to go from a soil test recommendation to the application rate. This calculator, created by Frank Sikora (Soil Test Coordinator), determines the application rate of one fertilizer, multiple fertilizers, manure, and lime (based on the quality of the lime).