LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 6B: FISHIERIES, SOIL, AND EMERGY METHODS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Table 1. Damage to resources and to ecosystem quality (LCIA) of the five crop rotation systems on five important
watersheds in Spain and arithmetic country average. Results are per m 2 and year of land occupation.
Ebro Duero Tajo Segura Guadalquivir Country average
± SD
Resources [MJse]
B-W-R a 6366 4125 9028 5778 9943 10410 ± 6290
B-W-P b 6612 4394 9293 5777 9841 10585 ± 6444
B-W-F c 10285 6978 14450 8948 15608 16198 ± 9652
B-W-OR (*)d 6000 3606 8691 5576 9156 9729 ± 5941
PP (*) -PP (*) -PP (*)e 1334 746 1602 975 1585 1776 ± 1142
Ecosystem quality [NPPD, decimal% of NPP lost]
B-W-R a 0.03 0.02 0.04 0.02 0.05 0.047 ± 0.028
B-W-P b 0.04 0.02 0.04 0.02 0.05 0.048 ± 0.028
B-W-F c 0.05 0.03 0.06 0.03 0.07 0.070 ± 0.043
B-W-OR (*)d 0.03 0.02 0.04 0.02 0.05 0.045 ± 0.027
PP (*) -PP (*) -PP (*)e 0.02 0.01 0.01 0.01 0.02 0.017 ± 0.006
a winter barley – winter wheat – rye
b winter barley – winter wheat – pea
c winter barley – winter wheat – unseeded fallow
d winter barley – winter wheat – oilseed rape
e poplar – poplar – poplar
Asterisks indicate crops for energy use.
4. Discussion
4.1 Soil-erosion impact assessment model
Two endpoint indicators for the AoP soil resources and ecosystem quality were proposed in order to include
in LCA impacts of land occupation on the soil erosion regulation ES. Compared to previous methods,
the added value of this research is that we provide CFs for the world which can be applied to assess land
occupation impacts of any type of human activity. Land transformation impacts were not addressed. Due to
the complex link between soil loss and human health damage, this impact pathway was excluded from the
assessment. CFs were regionalised on the grid-cell level without aggregating them on broader administrative
or ecological scales. Yet, a relevant and feasible scale of aggregation should be found in order to deal with
data gaps on location of processes, especially in the background system. However, this is a complex issue,
due to the huge variability of soils even at the landscape scale. Variability and uncertainty of location of
processes (e.g., plastic and fertiliser production of the background system) should also be assessed.
4.2 Case study on food and energy crops
A great variability of soil losses was recorded in the inventory step, depending on climatic and edaphic
conditions. The same trend was found in the impact assessment step, as the regionalised model developed
includes information on the sensitivity of the receiving ecosystem to impacts of land use. It is therefore very
important that land-use impact models include geospatial information in both the LCI and LCIA phases.
The results of the case study show that the poplar energy-crop rotation system in Spain can potentially reduce
erosion rates and environmental impacts per area-time unit compared to traditional cereal and legume
crop rotations. The use of other functional units (e.g., kg, MJ) might have led to different results. However,
the selection of non-area-based functional units when crops and rotations with different functions are being
compared is an unresolved issue in LCA (Núñez et al., 2012b). In relation to the recommended locations to
cultivate the analysed crop rotations to reduce soil erosion impacts, results indicate a trend. However, these
results should be interpreted with caution. They are valid for the analysed plots, but each specific case should
be studied separately, as soil erosion depends on plot level factors. Only the agricultural stage was included
in the assessment, thus the soil erosion model here developed should be applied to the overall life cycle (i.e.,
from the production of seed to the use of the crop or to the final waste management) to perform a proper
LCA study. The extension of the system boundary beyond the agricultural stage would be facilitated if unit
processes of LCI datasets had information on the amount of soil loss. To this end, the LANCA® tool can be
used, as already implemented in inventory flows of the GaBi software. However, we may consider the obtained
results for the agricultural stage to be representative of the total soil losses during the complete life
cycles of crops, as agriculture is by far the land use activity with higher soil erosion rates.
5. Conclusion
We developed a globally applicable, spatially differentiated method to account for land occupation impacts
in LCA, focusing on the aspect of soil erosion. LCI data needed was set up, CFs developed on a grid-
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