Unit process data for Rapeseed production in the U.S. wheat belt

Rapeseed is being considered as a potential feedstock for hydrotreated renewable jet (HRJ) fuel in the USA through its cultivation in rotation with wheat. The goal of this research was to determine the impact of soil C changes, induced through replacing the fallow period with rapeseed in rotation with wheat, and the effects it would have on emission of greenhouse gases (GHG) of rapeseed HRJ. The Intergovernmental Panel on Climate Change (IPCC) (Tier 1) method was used with modifications to determine the changes in soil C of wheat–wheat–rapeseed (WWR) relative to the reference wheat–wheat–fallow (WWF) rotation for 20 years of cultivation. The 27 case scenarios were conducted to study the impacts of changes in management practices (tillage practice and residue input) on changes in soil C for WWR rotation in multiple locations in 10 US states. The CO2 emissions resulting from soil C changes were incorporated into the rapeseed HRJ pathway in order to evaluate the GHG emissions.

These crop production simulations illustrate using the IPCC (Tier 1) method for calculating changes in soil C and the roundtable on sustainable biomaterials (RSB) method for estimating N2O emissions in different locations for the use in modeling the crop production portion of the HRJ lifecycle. Data are archived in a SimaPro .csv file, which can be imported into various life cycle assessment modeling tools.

The locations for cultivation of rapeseed were chosen from the top 5 wheat-producing counties in these states: CA, KS, MT, ND, NE, OK, OR, TX, SD, and WA (USDA 2007), which are the major wheat growing states in the USA. The cropping system of WWR rotation was assumed to be planted on long-term cultivated land, and soil C changes were calculated based on one hectare of land. The use of tillage practices and crop residue managements for wheat cultivation vary across the USA (Horowitz et al. 2010). Therefore, in this study, the cultivation of rapeseed in rotation with wheat was assumed to use a range of tillage practices and residue inputs. In order to simplify the analysis, the same tillage practices were assumed to be adopted for wheat and rapeseed. However, variations of residue inputs for both crops as low (L), medium (M), and high (H) without manure (Lasco et al. 2006) were included. These levels refer to the amounts of residue produced in growing the crops. Harvesting residues would further reduce residue inputs. However, residue harvest effects are not included in this analysis. The estimates of soil C change for WWR rotation were compared to WWF rotation as the reference system. Although variations of tillage practices are used for fallow rotation, reduced tillage is one of the practices that is commonly used for fallow rotation (Baker 2011). The proposed condition for the reference WWF was assumed to use high residue input for wheat, low residue input for the fallow period (since no crop is typically grown at this time), and reduced tillage for both wheat and fallow.

• Resource Title: rapeseed; average tillage mix; at farm; 9% moisture, csv.

  File Name: rapeseed; average tillage mix; at farm; 9% moisture.csv

  Resource Description: Metadata about the process and factors surrounding the rapeseed cultivation including processes and materials used, soil conditions, emissions, etc.




• Resource Title: Calculation_N2O emissions.

  File Name: Calculation_N2O emissions.xlsx




• Resource Title: Calculation_soil C change.

  File Name: Calculation_soil C change.xlsx




• Resource Title: Data Dictionary - Unit process data for Rapeseed production in the U.S. wheat belt.

  File Name: Data Dictionary - Unit process data rapeseed production US wheat belt.csv