Abstract• Purpose: Perennial crops globally provide a lot of fruit and other food products. They may also provide feedstock for bioenergy and have been, notably to this end, the subject of several LCA-based studies mostly focusing on energy and GHG balances. The purpose of this review was to investigate the relevance of LCAs on perennial crops, especially focusing on how the perennial crop specificities were accounted for in the farm stage modelling.• Methods: More than one hundred papers were reviewed covering 14 products from perennial crops: apple, banana (managed over several years), orange and other citrus fruits, cocoa, coconut, coffee, grape fruit, Jatropha oil, kiwi fruit, palm oil, olive, pear, and sugarcane. These papers were classified into three categories according to the comprehensiveness of the LCA study and depending on whether they were peer-reviewed or not. An indepth analysis of the goal and scope, data origin for farming systems, modelling approach for the perennial cropping systems, and methods and data for field emissions helped reveal the more critical issues and design some key recommendations to account better for perennial cropping systems in LCA.• Results and discussion: In the vast majority of the reviewed papers, very little attention was paid on integrating the perennial cropping cycle in the LCA. It is especially true for bioenergy LCA-based studies that often mostly focused on the industrial transformation without detailing the agricultural raw material production, although it might contribute to a large extent to the studied impacts. Some key parameters, such as the length of the crop cycle, the immature and unproductive phase, or the biannual yield alternance, were mostly not accounted for. Moreover the lack of conceptual modelling of the perennial cycle was not balanced by any attempt to represent the temporal variability of the system with a comprehensive inventory of crop managements and field emissions over several years.• Conclusions: According to the reviewed papers and complementary references, we identified the gaps in current LCA of perennial cropping systems and proposed a road map for scientific researches to help fill-in the knowledge-based gaps. We also made some methodological recommendations in order to account better for the perennial cycle within LCA considering the aim of the study and data availability.

-Biofuels are fuels produced from biomass, mostly in liquid form, within a time frame sufficiently short to consider that their feedstock (biomass) can be renewed, contrarily to fossil fuels. This paper reviews the current and future biofuel technologies, and their development impacts (including on the climate) within given policy and economic frameworks. Current technologies make it possible to provide first generation biodiesel, ethanol or biogas to the transport sector to be blended with fossil fuels. Still under-development 2nd generation biofuels from lignocellulose should be available on the market by 2020. Research is active on the improvement of their conversion efficiency. A ten-fold increase compared with current cost-effective capacities would make them highly competitive. Within bioenergy policies, emphasis has been put on biofuels for transportation as this sector is fast-growing and represents a major source of anthropogenic greenhouse gas emissions. Compared with fossil fuels, biofuel combustion can emit less greenhouse gases throughout their life cycle, considering that part of the emitted CO 2 returns to the atmosphere where it was fixed from by photosynthesis in the first place. Life cycle assessment (LCA) is commonly used to assess the potential environmental impacts of biofuel chains, notably the impact on global warming. This tool, whose holistic nature is fundamental to avoid pollution trade-offs, is a standardised methodology that should make comparisons between biofuel and fossil fuel chains objective and thorough. However, it is a complex and time-consuming process, which requires lots of data, and whose methodology is still lacking harmonisation. Hence the life-cycle performances of biofuel chains vary widely in the literature. Furthermore, LCA is a site-and timeindependent tool that cannot take into account the spatial and temporal dimensions of emissions, and can hardly serve as a decision-making tool either at local or regional levels. Focusing on greenhouse gases, emission factors used in LCAs give a rough estimate of the potential average emissions on a national level. However, they do not take into account the types of crop, soil or management practices, for instance. Modelling the impact of local factors on the determinism of greenhouse gas emissions can provide better estimates for LCA on the local level, which would be the relevant scale and degree of reliability for decision-making purposes. Nevertheless, a deeper understanding of the processes involved, most notably N 2 O emissions, is still needed to definitely improve the accuracy of LCA. Perennial crops are a promising option for biofuels, due to their rapid and efficient use of nitrogen, and their limited farming operations. However, the main overall limiting factor to biofuel development will ultimately be land availability. Given the available land areas, population growth rate and consumption behaviours, it would be possible to reach by 2030 a global 10% biofuel share in the transport sector, contributing to l...

Nitrous oxide (N2O) emissions comprise the major share of agriculture's contribution to greenhouse gases; however, our understanding of what is actually happening in the field remains incomplete, especially concerning the multiple interactions between agricultural practices and N2O emissions. Soil compaction induces major changes in the soil structure and the key variables controlling N2O emissions. Our objective was to analyse the ability of a process-based model (Nitrous Oxide Emissions (NOE)) to simulate the impact of soil compaction on N2O emission kinetics obtained from field experiments. We used automatic chambers to continuously monitor N2O and CO2 emissions on uncompacted and compacted areas in sugar beet fields during 2 years. Soil compaction led to smaller CO2 emissions and larger N2O emissions by inducing anoxic conditions favourable for denitrification. Cumulative N2O emissions during the crop cycles were 944 and 977 g N ha?1 in uncompacted plots and 1448 and 1382 g N ha?1 in compacted plots in 2007 and 2008, respectively. The NOE model (H´enault et al., 2005) simulated 106 and 138 g N2O-N ha?1 in uncompacted plots and 1550 and 650 g N2O-N ha?1 in compacted plots in 2007 and 2008, respectively, markedly under-estimating the nitrification rates and associated N2O emissions. We modified the model on the basis of published results in order to better simulate nitrification and account for varying N2O fractions of total end-products in response to varying soil water and nitrate contents. The modified model (NOE2) better predicted nitrification rates and N2O emissions following fertilizer addition. Using a fine vertical separation of soil layers of configurable, but constant, thickness (1 cm) also improved the simulations. NOE2 predicted 428 and 416 g N-N2O ha?1 in uncompacted plots and 1559 and 1032 g N- N2O ha?1 in compacted plots in 2007 and 2008, respectively. These results show that a simple process-based model can be used to predict successfully the post-fertilizer addition kinetics of N2O emissions and the impact of soil compaction on these emissions. However, large emissions later on during the cropping cycle were not captured by the model, emphasizing the need for further research. (Résumé d'auteur

No abstract

Nitrogen (N) losses in agroecosystems are a major environmental and economic issue. This issue is particularly pronounced in oil palm cultivation because oil palm production area is expected to increase to 12 Mha by 2050. N fertilization in oil palm plantations is mainly provided by mineral fertilizers, palm oil mill by-products, and biological fixation using legume cover crops. N loss has a major environmental impact during cultivation. For instance, 48.7 % of the greenhouse gases emitted to produce 1 t of palm oil fruit are due to N fertilization. Actually, there is little comprehensive knowledge on how to calculate N budgets in oil palm plantation in order to optimize fertilization, taking into account N leaching and N gases emissions. Here we modeled knowledge about all N fluxes in an oil palm field following standard management practices of industrial plantations, on a mineral soil, from planting to felling after a 25-year-growth cycle. The largest fluxes are internal fluxes, such as oil palm uptake, with 40-380 kg N ha, and the decomposition of felled palms at the end of the cycle, with 465-642 kg N ha

The Roundtable on Sustainable Palm Oil (RSPO) is a non-profit association promoting sustainable palm oil through a voluntary certification scheme. Two successive science-based working groups on greenhouse gas (GHG) were active in RSPO from 2009 to 2011, with the aim of identifying ways of achieving meaningful and verifiable reductions of GHG emissions. One of the outputs of the second group is PalmGHG, a GHG calculator using the life cycle assessment approach to quantify major sources of emissions and sequestration for individual palm oil mills and their supply base. A pilot study was carried out in 2011 with nine RSPO member companies that gave an average of 1.67 t CO2e/t crude palm oil (CPO), with a range of ?0.02 to +8.32 t CO2e/t CPO. Previous land use and the area of peat soil used were the main causes of the variation. Further modifications to PalmGHG continue to be made in order to make the tool more flexible and comprehensive, to refine default values, and to render it more user-friendly. (Résumé d'auteur

-Palm oil is nowadays the first vegetable oil consumed worldwide. Given the world population growth and the increasing demand in fat for food and fuel, the increase in oil palm production is expected to continue. It is thus important to find ways of reducing the ecological impact of oil palm plantations at both the agroecosystem and the mill supply area levels, by improving agricultural practices and land uses. This is where agroecology can play a very critical role. The present article gathers short stories on agroecological practices currently taking place in oil palm plantations in South-East Asia. Such stories notably highlight the importance of the various palm co-products and how appropriate recycling strategies can allow for reducing external inputs to both the field and the mill. Besides limiting environmental impacts thanks to such savings, several coproducts used as organic amendments can even help to maintain or enhance soil quality. Other stories explored agroecological practices developed for biological controls. Although integrated pest management has been applied in palm plantations for a long time, the underlying mechanisms are still not fully deciphered and practices still need to be improved. More knowledge is needed in order to better account for the holistic role of biodiversity and arbitrate trade-offs between practices and ecosystem services, at both plantation and landscape levels.Keywords: palm oil / agroecology / biological control / recycling / composting / soil quality Résumé -Pratiques agroécologiques en plantations de palmier à huile : exemples de terrain. L'huile de palme est aujourd'hui la première huile végétale consommée au monde. Étant donné la croissance démographique mondiale et la demande accrue en corps gras pour l'alimentation et les biocarburants, l'augmentation de la production d'huile de palme devrait perdurer. Il est ainsi primordial de trouver des moyens de production permettant de réduire l'impact écologique des plantations de palmier à huile, à la fois à l'échelle de l'agroécosystème et celle du bassin d'approvisionnement de l'huilerie, en améliorant les pratiques et la gestion des usages des sols. Les principes de l'agroécologie peuvent aider à développer des solutions à ces diverses échelles. Cet article rassemble diverses histoires courtes illustrant des pratiques agroécologiques mises en place dans des plantations de palmier à huile en Asie du Sud-Est. Ces illustrations mettent en évidence l'importance des nombreux co-produits issus du palmier et leur rôle clé dans les stratégies de recyclage pour réduire le recours aux intrants externes pour la plantation comme pour l'huilerie. Au-delà de la réduction des impacts environnementaux du fait de ces économies d'intrants, certains co-produits restitués en plantation peuvent également permettre de maintenir, voire d'améliorer, la qualité des sols. D'autres histoires courtes parcourent quelques autres pratiques agroécologiques dans le domaine de la lutte intégrée. Bien que de nombreuses pratiques de contrôle bi...

No abstract