Energy Balance and Greenhouse Gas Emission of Dryland Camelina As Influenced By Tillage and Nitrogen.

Despite the great potential of camelina (Camelina sativa L. Crantz) as an outstanding biofuel feedstock, in-farm energy flow of camelina has received insufficient attention from researchers. The impacts of tillage practice [conventional tillage (CT) and no-tillage (NT)] and nitrogen (N) fertilization (0, 45, 90 kg ha^-1) on energy balance and greenhouse gas (GHG) emission (kg C eq ha^-1) of camelina production in a dryland farming system at central Montana was studied. Results indicated that energy input and GHG emission were 5 and 8% lower in NT than in CT. Application of 45 and 90 kg N ha^-1 increased camelina energy input by 186 and 365% while increased energy output by only 21 and 64%, respectively. These tradeoffs between energy output and energy input in response to N fertilization resulted in no variations in net energy but lower energy efficiency in response to the N fertilization. When no external N was applied, GHG emission was 32.0 kg C eq ha^-1 (averaged across tillage systems). Application of 45 and 90 kg ha^-1, increased GHG emission by 206 and 389%, respectively. Overall, N fertilizer had the biggest share in total energy input of camelina. Averaged over all experimental treatments, 14945 MJ ha^-1 net energy was obtained from camelina in this study which shows the potential of this crop as a bioenergy feedstock for this low-input dryland farming system. Our results showed that implementation of NT is stringly recommendable for camelina production in this region. Moreover, improvement of N use efficiency has the highest priority to improve energy performance and reduce environmental emissions of camelina in this environment.