Field Operations

Methods 5.0

upstream
on-farm mechanical
Energy and emissions of fuel used in field activities during the crop interval.
Published

September 22, 2025

Introduction

Field operations are done in the field with machinery and include activities such as tilling or cultivating the soil, applying fertilizer or manure, spraying crop protectants, and harvesting. These activities consume fuel energy and release GHG emissions. How much fuel is used in each activity is determined with the Conservation Resources-Land Management Operations Database [CR-LMOD; Carlson et al. (2018)]. Consider the difference in fuel used between driving across a field with sprayer arms out to the sides above the crop and dragging tillage implements deep through the soil. The total amount of fuel used for all field activities within a single crop interval, from pre-planting activities to harvest, determines the total energy use and GHG emissions for that crop interval.

The energy and emissions associated with manure transportation and crop transportation are accounted for separately from field operations.

Soybean harvest operation. Photo: Ginger Jordan.

Soybean harvest operation. Photo: Ginger Jordan.

Methods

Inputs

Input Value Units Symbol
Field area Defined by user-entered field boundary ac
ha		 \(A\)
Fuel usage per area for activity \(i\) CR-LMOD value gal/ac
gal/ha		 \(V_{i_{A}}\)
Fuel type Diesel
Fuel energy ~ 144.9 MJ gal-1 diesel \(E_{fuel}\)

Steps

  1. Finalize the rotation of field activities in the crop interval.

  2. For each activity, look up the amount of fuel used per acre (\(V_{i_{A}}\)) from the CR-LMOD and multiply by \(A\) to determine \(V_i\), the amount of fuel used by activity \(i\) at the field level.

  3. Sum all \(V\) from all activities to determine total fuel used at the field level.

  4. Calculate all direct and indirect energy and emission components

    • For example, to calculate the upstream energy and emissions associated with the diesel manufacturing, the amount of diesel is multiplied by a given GHG component’s energy or emission factor per gallon (Table 1) .

  5. Lastly, standardize to kg CO2e with Global Warming Potential factors.

Example

  • Field size = 60 ha
  • CR-LMOD estimated total fuel per acre = 28 gal/acre
    • converted to 69.2 gal/ha
  • Fuel use at the whole field level = 69.2 * 60 = 4,152 gallons of diesel

Tables

Impact Factors

Table 1: Energy and emissions associated with the production and use of fuel in field operations.
metric system_boundary source_category source_detail CO2_fossil CO2_biogenic CH4_fossil CH4_biogenic N2O NF3 SF6 MJ
Energy Use Upstream Energy use associated with production of fuels Field Operations | Diesel (ag equipment) 0.0000000 0 0.0000000 0 0.0000000 NA NA 15.9391
GHG Emissions Upstream GHG emissions associated with production of fuels Field Operations | Diesel (ag equipment) 0.9747006 0 0.0023290 0 0.0000195 NA NA 0.0000
Energy Use On-Farm Mechanical Energy use associated with mobile machinery Field Operations | Diesel (ag equipment) 0.0000000 0 0.0000000 0 0.0000000 NA NA 144.9446
GHG Emissions On-Farm Mechanical GHG emissions associated with mobile machinery Field Operations | Diesel (ag equipment) 10.2037634 0 0.0012692 0 0.0010693 NA NA 0.0000

References

Carlson, Jack, Lucas Yaege, Joel Poore, Larry Wagner, James Frankenberger, and Olaf David. 2018. “Standardizing Cropping System Data for Integrated Agricultural Resource Assessment.” International Congress on Environmental Modelling and Software, June. https://scholarsarchive.byu.edu/iemssconference/2018/Stream-C/16.