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Sensitivity analysis of greenhouse gas emissions from a pork production chain
- Groen, E.A., van Zanten, H.H.E., Heijungs, R., Bokkers, E.A.M., de Boer, I.J.M.
- Journal of cleaner production 2016 v.129 pp. 202-211
- Hordeum vulgare, Zea mays, animal manure management, barley, corn, crop management, crops, diet, farmers, feed conversion, feed intake, feeding methods, fertilizer rates, grain yield, greenhouse gas emissions, greenhouse gases, meat production, methane, mortality, multipliers, nitrogen fertilizers, nitrous oxide, piglets, pork, reliability, sows, uncertainty
- This study aimed to identify the most essential input parameters in the assessment of greenhouse gas (GHG) emissions along the pork production chain. We identified most essential input parameters by combining two sensitivity-analysis methods: the multiplier method and the method of elementary effects. The former shows how much an input parameter influences assessment of GHG emissions, whereas the latter shows the importance of input parameters on uncertainty in the output. For the method of elementary effects, uncertainty ranges were implemented only for input parameters that were identified as being most influential based on the multiplier method or that had large uncertainty ranges based on the literature. Results showed that the most essential input parameters are the feed-conversion ratio, the amount of manure, CH4 emissions from manure management and crop yields, especially of maize and barley. Combining the results of both methods allowed derivation of mitigation options, either based on innovations (e.g. novel feeding strategies) or on management strategies (e.g. reducing mortality rate), and formulation of options for improving reliability of the results. Mitigation options based on innovations were shown to be most effective when directed at improving the feed-conversion ratio; decreasing the amount of manure produced by pigs; improving maize, barley and wheat yields; decreasing the number of sows or piglets per growing pig needed and improving efficiency of N-fertiliser production. Mitigation options based on management strategies were shown to be most effective when farmers strive to reduce feed intake, reduce application of N fertiliser to maize and barley, and reduce the number of sows per growing pig needed towards best practices. Finally, the method of elementary effects showed that reliability of assessing GHG emissions of pork production could be improved when uncertainty ranges are reduced, for example, around direct and indirect N2O emissions of the main feed crops in the pig diet and the CH4 emissions of manure. Also the reliability could be improved by improving data quality of the most essential parameters. Combining two types of sensitivity-analysis methods identified the most essential input parameters in the pork production chain. With this combined analysis, mitigation options via innovations and management strategies were derived, and parameters were identified that improved reliability of the results.