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Increasing the level of feed autonomy isusually considered as a prerequisite for conversion of cattle farms to organic management. This study is aimed at generating references for organic dairy and beef production through a technical and economic assessment of feed autonomy in commercial farms. Data were collected in 2014 and 2015 on 11 farms located in distinct agricultural regions of Wallonia, Belgium. Dry matter (DM) production, animal performance and all cash in- and outflows were recorded. Economic efficiency (EE) was computed as the share of the feed margin, i.e., the gross product minus the total feed and processing costs, in the gross product. The mean level of mass feed autonomy (FAm) was 94 ± 6%. Feed production costs(p 65% had a level of FAm ≥ 90%; however, one farm with FAm ≥ 90% had a mean EE of 55% over both study years. This observation suggested that a 90% level of FAm is necessary, but not sufficient, to increasing the level of feed autonomy is usually considered as a prerequisite for conversion of cattle farms to organic management. This study is aimed at generating references for organic dairy and beef production through a technical and economic assessment of feed autonomy in commercial farms. Data were collected in 2014 and 2015 on 11 farms located in distinct agricultural regions of Wallonia, Belgium. Dry matter (DM) production, animal performance and all cash in- and out flows were recorded. Economic efficiency (EE) was computed as the share of the feed margin, i.e., the gross product minus the total feed and processing costs, in the gross product. The mean level of mass feed autonomy (FAm) was 94 ± 6%. Feed production costs(p 65% had a level of FAm ≥ 90%; however, one farm with FAm ≥ 90% had a mean EE of 55% over both study years. This observation suggested that a 90% level of FAm is necessary, but not sufficient, to be economically efficient in organic cattle farming. Four production systems with EE > 65% and thus FAm ≥ 90% were finally characterized based on the observed crop rotations, overall DM yields, stocking rates and animal performances.

Description of the subject. Many decision support tools (DSTs) have been developed to help dairy farmers optimally manage the high variability in the quality and availability of grass-based fodder, but their adoption rate remains low. Objectives. The objective was to characterize and understand the adoption rate of DSTs related to using grass-based fodder. Methodology. A sample of 61 Walloon (Belgium) dairy farmers responded to an online survey concerning their current use of 23 DSTs related to using grass-based fodder either directly (pasture or grassland) or indirectly (feeding or techno-economic), as well as barriers to and incentives for adopting them, their current interest in DSTs, and satisfaction with the guidance on using these DSTs. Results. Pasture management DSTs were used the least, even though farmers were the most interested in them. Farmers used simple indicators rather than software or automated tools. Farmers indicated that DSTs were too expensive and time consuming, even if they could ultimately save them time and money. Continuing education is lacking. Four types of users were identified who influence the use of DSTs: high user no grazing (H-NG), high user traditional or technical grazing (H-T/TG), low user traditional grazing (L-TG), and moderate user organic (M-ORG). Conclusions. Communicating with end-users during each step of DST development would help (1) identify the specific needs of a diverse set of dairy farmers and (2) develop DSTs that better correspond to their practices. More long-term guidance is required to inform farmers about existing DSTs and to transfer the knowledge required to use them.

• Crop diversification is a dynamic pathway towards sustainable agrifood systems. • Technological and institutional barriers restrict uptake of crop diversification. • More coordination and cooperation among agrifood system stakeholders is required. • The European Crop Diversification Cluster calls for multiactor networks. European cropping systems are often characterized by short rotations or even monocropping, leading to environmental issues such as soil degradation, water eutrophication, and air pollution including greenhouse gas emissions, that contribute to climate change and biodiversity loss. The use of diversification practices (i.e., intercropping, multiple cropping including cover cropping and rotation extension), may help enhance agrobiodiversity and deliver ecosystem services while developing new value chains. Despite its benefits, crop diversification is hindered by various technical, organizational, and institutional barriers along value chains (input industries, farms, trading and processing industries, retailers, and consumers) and within sociotechnical systems (policy, research, education, regulation and advisory). Six EU-funded research projects have joined forces to boost crop diversification by creating the European Crop Diversification Cluster (CDC). This Cluster aggregates research, innovation, commercial and citizen-focused partnerships to identify and remove barriers across the agrifood system and thus enables the uptake of diversification measures by all European value-chain stakeholders. The CDC will produce a typology of barriers, develop tools to accompany actors in their transition, harmonize the use of multicriteria assessment indicators, prepare policy recommendations and pave the way for a long-term network on crop diversification.

Crop diversification represents a key lever to support the development of sustainable agri-food systems. Knowledge on trade-offs and carry over effects from different crop diversification strategies is essential to inform agricultural stakeholders of potential costs and benefits. This knowledge is limited by existing data and performance measures predominantly focused on single crops, rather than complete rotations. Moreover, sustainability performance indicators are often used for assessment purposes, rather than supporting stakeholder learning and actions. A new set of 32 indicators was developed to address these needs, and used to evaluate the environmental, economic and social sustainability of the diversified agricultural systems highlighted in the case studies, which are often characterized by data availability constraints. This approach was tested in France, Germany and Italy to determine a critical ex-post diagnosis of the existing systems, and for the assessment of ex-ante innovative scenarios. The results will be used to support these case studies in the identification and design of more sustainable agricultural systems. Although the framework is based on feasible and proxy indicators, the assessment outcomes have allowed local actors to reflect on the effects generated by the implemented crop diversification strategies. Key issues include trade-offs occurring between optimizing economic and environmental performance.

Life cycle assessment (LCA) is a useful tool for investigating the environmental performance of agricultural products. For many crop-based products, the agricultural production step shows substantial impacts in LCA results. Using the illustrative case of cereal production in Wallonia, Belgium, the study uses sensitivity analyses to explore the parameters to be adjusted in priority when conducting a local LCA for crop production, taking into account uncertainties tied to input and output inventory data and impact characterization factors. The analysis investigated local specificities in the production of eight cereal crops in Wallonia. Cropping systems were modeled according to accounting data from representative farms, including areas, yields, inputs, and machinery. Sensitivity and uncertainty analyses for input parameters and methodological choices were performed. The following parameters were evaluated: the influence of the functional unit (kg, ha, €), the link between yield and LCIA results, the relevance of using up-to-date data for mineral fertilizer production, the type of mineral fertilizer, the model for direct field emission calculation, and the allocation rules. We observed that the use of several functional units embracing the multifunctional role of agriculture enables identifying crops with low impacts per kilogram, hectare, and euro at the same time. The cereal production steps with the greatest impact were mineral fertilizer production (up to 84% of the total impact, depending on crop and impact category) and emissions from the application of mineral (up to 65%) and organic (up to 94%) fertilizers. Sensitive parameters to be adjusted in priority were identified. Despite the high correlation between yield and results, simply extrapolating impacts on the basis of yield seemed mostly inappropriate. Using updated data for mineral fertilizer production reduced impacts by 6–160%. Shifting models for field emission calculation influenced acidification and eutrophication by 5–142%. Hypotheses on allocation factors affected results by 10–26%. An LCA for the production of major Walloon cereals was conducted taking into account local cropping practices and yields. The parameters relevant for conducting a regional LCA of crop production were identified and discussed in comparison with generic data and models. As LCA is an iterative process, further improvements would include the use of more specific models for direct field emission calculation. The results could serve as a reference for products using Walloon cereals and help enhance the quality of LCAs conducted for these products.

Agent-Based Models (ABMs) are becoming a widespread approach to model human-environment interactions. They belong to the class of individual-based modelling approaches, which allow a bottom-up representation of the system being modelled, eliciting its macro-level evolution while modelling the micro-level behavior of its individuals. This paper deals with the application of an ABM to simulate future crop patterns in the Grand-Duchy of Luxembourg under a pre-defined scenario. The simulated scenario deals with the introduction of a “green consciousness” component in farmers' decisions, substituting a purely rational approach based only on profit maximization. The results of the ABM are used to perform a life cycle assessment of Luxembourg's agricultural system. The paper first describes the difficulties and the challenges connected with building an ABM for agriculture and then shows the results of the selected case study. The results show that, from a lifecycle perspective, a “greenness” criterion aimed only at reducing greenhouse gases emissions reveals patently a sub-optimal choice and causes burden shifts to other impact categories. Finally the ABM-based (bottom-up) approach is compared with a top-down approach applied in a previous study by the same authors to model the same system. Assets and drawbacks of the two approaches are highlighted.

The study examined the prediction error of near infrared reflectance spectroscopy of faeces (FNIRS) in estimations of in vivo organic matter digestibility (OMD) and dry and organic matter voluntary intake (DMVI and OMVI) of forages by ruminants in established calibration datasets from our laboratories. It also examined the repeatability of the FNIRS measurements of these parameters and the proportion of grass and clover in ingested forage. The prediction error of NIRS calibrations depends on the accuracy and precision of reference data. In this study, the variability in reference data for OMD, DMVI and OMVI was less than 10% of the mean. Correction for the error in the reference method almost halved the standard error of prediction (SEP) for OMD to 0.0155. For DMVI and OMVI, the corrected SEP was 8–9 g/kg BW 0.75 , similar to the apparent SEP. These results suggested that the FNIRS calibrations were precise enough to predict OMD adequately, but probably not DMVI or OMVI. The repeatability of FNIRS spectra and predictions assessed by repeated measurements of the same sample was satisfactory for all tested parameters. For OMD, DMVI, OMVI and the grass and clover proportion of the ingested forage, prediction repeatability was lower than, or similar to, the standard error of cross-validation (SECV) of the FNIRS calibration. The study showed that FNIRS could be a reliable method for predicting the OMD of ruminants, but the prediction of voluntary intake with acceptable error was less satisfactory because of uncertainties in the FNIRS calibration models.

We build an ABM for simulation of incentives for maize to produce bio-fuels in Luxembourg with an aim to conduct life cycle assessment of the additional maize and the consequent displacement of other crops in Luxembourg. This paper focuses on the discovery of market price for crops. On the supply side we have farmers who are willing to sell their produce based on their actual incurred costs and an expected markup over costs. On the demand side, we have buyers or middlemen who are responsible for quoting prices and buying the output based on their expectation of the market price and quantity. We have N buyers who participate in the market over R rounds. Each buyer has a correct expectation of the total number of buyers in each market. Thus in each round, the buyer bids for a quantity \(q_b^r=\frac {Q_b^e}{N \times R}\), where \(Q_b^e\) is the expected total output of a crop. The buyer at each round buys \(\min (q_b^r,S_t^r)\), the minimum of the planned purchase at each round r and the total supply \(S_t^r\) by farmers in the round at a price \(p_b^r\). The market clears over multiple rounds. At each round, the buyers are sorted by descending order of price quotes and the highest bidder gets buying priority. Similarly the farmers are sorted according to the ascending order of quotes. At the end of each round, the clearance prices are visible to all agents and the agents have an option of modifying their bids in the forthcoming rounds. The buyers and sellers may face a shortfall which is the difference between the target sale or purchase in each round and the actual realised sale. The shortfall is then covered by smoothing it over future rounds (1–4). The more aggressive behaviour is to cover the entire shortfall in the next round, while a more calm behaviour leads to smoothing over multiple (4) rounds. We find that there is a statistically distinct distribution of prices and shortfall over smoothing rounds and has an impact on the price discovery.

Increasing input self-sufficiency is often viewed as a target to improve sustainability of dairy farms. However, few studies have specifically analysed input self-sufficiency, by including several technical inputs and without only focussing on animal feeding, in order to explore its impact on farm sustainability. To address this gap, our work has three objectives as follows: (1) identifying the structural characteristics required by specialised dairy farms located in the grassland area to be self-sufficient; (2) analysing the relationships between input self-sufficiency, environmental and economic sustainability; and (3) studying how the farms react to a decrease in milk price according to their self-sufficiency degree. Based on farm accounting databases, we categorised 335 Walloon specialised conventional dairy farms into four classes according to their level of input self-sufficiency. To this end, we used as proxy the indicator of economic autonomy – that is, the ratio between costs of inputs related to animal production, crop production and energy use and the total gross product. Classes were then compared using multiple comparison tests and canonical discriminant analysis. A total of 30 organic farms – among which 63% had a high level of economic autonomy – were considered separately and compared with the most autonomous class. We showed that a high degree of economic autonomy is associated, in conventional farms, with a high proportion of permanent grassland in the agricultural area. The most autonomous farms used less input – especially animal feeding – for a same output level, and therefore combined good environmental and economic performances. Our results also underlined that, in a situation of decrease in milk price, the least autonomous farms had more latitude to decrease their input-related costs without decreasing milk production. Their incomes per work unit were, therefore, less impacted by falling prices, but remained lower than those of more autonomous farms. In such a situation, organic farms kept stable incomes, because of a slighter decrease in organic milk price. Our results pave the way to study the role of increasing input self-sufficiency in the transition of dairy farming systems towards sustainability. Further research is required to study a wide range of systems and agro-ecological contexts, as well as to consider the evolution of farm sustainability in the long term.

The biomethane yield of various energy crops, selected among potential alternatives to maize in the Greater Region, was assessed. The biomass yield, the volatile solids (VS) content and the biochemical methane potential (BMP) were measured to calculate the biomethane yield per hectare of all plant species. For all species, the dry matter biomass yield and the VS content were the main factors that influence, respectively, the biomethane yield and the BMP. Both values were predicted with good accuracy by linear regressions using the biomass yield and the VS as independent variable. The perennial crop miscanthus appeared to be the most promising alternative to maize when harvested as green matter in autumn and ensiled. Miscanthus reached a biomethane yield of 5.5 ± 1 × 10(3)m(3)ha(-1) during the second year after the establishment, as compared to 5.3 ± 1 × 10(3)m(3)ha(-1) for maize under similar crop conditions.

The chemical characteristics of 95 miscanthus giganteus ( Miscanthus × giganteus J.M. Greef & Deuter ex Hodk. & Renvoize), 150 switchgrass ( Panicum virgatum L.), 79 spelt straw ( Triticum aestivum L. ssp. spelta (L.) Thell.), 145 fiber sorghum ( Sorghum bicolor (L.) Moench), 27 “cocksfoot–alfalfa” mixture ( Dactylis glomerata L.– Medicago sativa L.), 175 tall fescue ( Festuca arundinacea Schreb.), 54 immature rye ( Secale cereale L.), 146 fiber corn ( Zea mays L.), 80 hemp ( Cannabis sativa L.) and 46 jerusalem artichoke ( Helianthus tuberosus L.) independent fibrous biomass samples are summarized in the present paper. Analyzed biomasses show 2 distinctive patterns at the level of both the chemical and hemicellulosic composition. The individual composition for each type of biomass is relatively constant despite the diversity of the crop conditions (year, area, cultivar, nitrogen fertilization level). Fiber corn harvested in autumn offers the highest potential for both digestible organic matter and total bioethanol, owing to its high dry biomass yield, high structural carbohydrates and starch contents and high digestibility. Both fiber corn and miscanthus harvested in autumn offer the highest energy yields per unit area (hm 2 ) (as higher heating values), owing to their significantly higher dry biomass yield as compared to the other crops. In all cases, autumn harvest offers better yields than late winter harvest, mainly due to a loss of harvestable biomass during winter, and not significantly due to the evolution of their composition.

BACKGROUND: An optimal valorization of plant biomasses to produce biofuels requires a good knowledge of the available contents and molecular composition of the main chemical components, which changes with the harvesting date. Therefore, we assessed the influence of harvesting date on the chemical characteristics of various energy crops in the context of their conversion to biofuels. RESULTS: We showed that the biomass chemical composition, enzymatic digestible organic matter, bioethanol and thermal energy production potential for each species are impacted by the harvesting date. The proportion of enzymatically digestible organic matter decreases as the harvesting date is delayed. This is related to the increase in cellulose and lignin contents. The suitability of the biomasses for bioethanol production increases with harvest stage, as the total carbohydrates content increases. The suitability of the biomasses as a source of thermal energy increases according to the harvesting date as the proportion of organic matter increases and the content of mineral compounds decreases. For all investigated energy conversions, the best harvesting period is autumn, because the significantly higher crop dry matter yield largely compensates for the sometimes slightly less favorable chemical characteristics. CONCLUSION: While the biomass composition of energy crops changes with harvest stage, the dry biomass yield per unit area is the main factor that controls the total amount of chemical components, digestible organic matter, bioethanol and thermal energy that can be expected to be harvested per unit area. The biomass compositions presented in this paper are essential to investigate their suitability for bioenergy conversion. © 2013 Society of Chemical Industry.

The chemical composition of 1052 samples covering 49 plant species is summarized in this paper. The analyzed biomasses offer a wide range of chemical compositions, monosaccharidic compositions of hemicelluloses, enzymatically digestible organic matter, and bioethanol potential. Nevertheless, their thermal energy value remains in a narrow range on a dry matter basis. Biomasses that were identified as best suited for anaerobic digestion are characterized by low contents of cellulose, hemicelluloses, and lignin and high contents of non-structural constituents. Biomasses most suited for combustion present the lowest content of mineral compounds, and the most adequate biomasses for bioethanol conversion have high contents of total carbohydrates. Interestingly, the observed chemical compositions tend to cluster the biomasses in composition groups that also correspond to phylogenetic groups: commelinids, non-commelinid magnoliophyta, and pinophyta species. Some groups can clearly be subdivided into fibrous and m...

This paper presents a new cognitive mapping approach for analysing systems of practices in social-ecological systems. These systems are mapped from people's views collected during open-ended interviews. Cognitive maps are made up of diverse variables (e.g., operations, drivers, constraints) linked to each other by a range of relationships: cause-effect, fluxes of matter, information flows and sequence of two operations. Individual cognitive maps heuristically model the practices and decision-making processes expressed by interviewees. The mathematical formulation of cognitive maps allows individual cognitive maps to be aggregated into a social cognitive map. The latter can be used to model the system of practices used by a particular group of people. Using this approach, we analysed the practices and decision-making processes linked to grassland management in a Belgian grassland-based livestock farming system. Our work confirmed that a social cognitive map could be drawn up for multiple locations. The results showed how this inductive cognitive mapping approach overcame two limitations frequently highlighted in previous studies: the diverse interpretations of variables and relationships; and the difficulty in revealing the rationale in cognitive maps. © 2012 Elsevier B.V.

The objective of this study was to validate near-infrared reflectance spectroscopy (NIRS) applied to faeces (FNIRS) for estimating the grass in vivo organic matter digestibility (G-OMD) and the grass dry matter intake (G-DMI, kg/d) of concentrate-supplemented grazing dairy cows. The G-OMD estimates from one FNIRS model were compared with two estimates using faecal nitrogen indicator (FNI) methods. Similarly, two FNIRS models were compared with the ratio technique (RT) and with three animal performance methods (APM) for estimating G-DMI. The results were analysed at cow and herd level in two grazed paddocks (P1 and P2) in a rotational grazing scheme. For both G-OMD and G-DMI, the FNIRS estimations were correlated (P r = 0.61 for G-OMD and r = 0.63–0.88 for G-DMI). Depending on the estimation method, the G-OMD varied from 0.689 (FNIRS) to 0.773 (FNI). The FNI estimates were generally higher and were similar to the G-OMD estimates obtained from NIRS analyses of grass sampled in the field. The FNIRS and FNI estimates were biased at cow and paddock level by 0.01–0.1 digestibility units (P Depending on the estimation method, the G-DMI estimates varied from 11.9 to 16.4 kg/d. FNIRS and APM produced similar estimates of G-DMI at both cow and herd level. The RT estimates of G-DMI were 3 kg/d higher than the FNIRS and APM estimates (P For both G-OMD and G-DMI and for all the estimation methods, inter-cow and intra-paddock variations, expressed through the coefficient of variation (SD/mean), ranged from 0.05 to 0.40. As the accuracy of the FNIRS models, expressed through the standard error of cross validation (SECV), was lower than these inter-animal and intra-paddock variations, we suggest that FNIRS could be used to record, quickly and easily, the evolution of grass digestibility and the intake of grazing dairy cows. These estimates could be implemented through decision-support systems aimed at improving the management of grazing dairy herds.

The diversity of beef cattle production systems in terms of diet, manure management and building design results in variation in greenhouse gas (GHG) emissions and the opportunities to reduce them. Within this context, we studied the effect of the varying proportions of concentrate (37-85% of DM) in the diet of Belgian Blue heifers on CH 4 and N 2O emissions from a tie-stall system (barn and solid manure storage). Trials were conducted over two consecutive periods in which manure was stored mainly in winter and spring. Increasing the proportions of concentrate in the diet reduced the GHG (CH 4+N 2O) emissions from the barns from 8.5±1.6 to 1.9±0.4kgCO 2eq/kg live-weight gain, but had not significant influence on the emissions from the stored solid manure. Seasonal variation in gas emissions was observed, with lower emissions from stored solid manure in winter than in spring (159±25 and 314±49mg CO 2, 0.14±0.02 and 2.47±0.78mg CH 4, and

The control of Rumex obtusifolius, even with the use of herbicides, is difficult in permanent grasslands where R. obtusifolius reduces both productivity and nutritive value of herbage. It is important to find alternative approaches to managing R. obtusifolius. Two greenhouse experiments were conducted to compare the impact of different cutting frequencies, which simulated grazing (three cuts), silage making (two cuts) and hay making (one cut) on shoot and root measurements of the vigour of R. obtusifolius. In both experiments the same cutting frequencies were imposed but in Experiment 1 the treatments were imposed for 2 years and in Experiment 2 for 1 year. Compared to the silage-making and hay-making treatments, there was a reduction in the vigour of the aerial parts of R. obtusifolius on the grazing treatment, associated with a reduction in the number of leaves (Experiment 1), in the size of the largest leaf (Experiment 1) and in the herbage mass of dry matter (Experiments 1 and 2). Roots had higher concentrations of total soluble sugar and lower concentrations of starch in the grazing treatment than in the other treatments. These results showed that a reduction in the vigour of R. obtusifolius in permanent grasslands is possible only if the plants are submitted to a high frequency of defoliation under cutting or grazing.

Producing biogas via anaerobic digestion is a promising technology for meeting European and regional goals on energy production from renewable sources. It offers interesting opportunities for the agricultural sector, allowing waste and by-products to be converted into bioenergy and bio-based materials. A consequential life cycle assessment (cLCA) was conducted to examine the consequences of the installation of a farm-scale biogas plant, taking account of assumptions about processes displaced by biogas plant co-products (power, heat and digestate) and the uses of the biogas plant feedstock prior to plant installation. Inventory data were collected on an existing farm-scale biogas plant. The plant inputs are maize cultivated for energy, solid cattle manure and various by-products from surrounding agro-food industries. Based on hypotheses about displaced electricity production (oil or gas) and the initial uses of the plant feedstock (animal feed, compost or incineration), six scenarios were analyzed and compared. Digested feedstock previously used in animal feed was replaced with other feed ingredients in equivalent feed diets, designed to take account of various nutritional parameters for bovine feeding. The displaced production of mineral fertilizers and field emissions due to the use of digestate as organic fertilizer was balanced against the avoided use of manure and compost. For all of the envisaged scenarios, the installation of the biogas plant led to reduced impacts on water depletion and aquatic ecotoxicity (thanks mainly to the displaced mineral fertilizer production). However, with the additional animal feed ingredients required to replace digested feedstock in the bovine diets, extra agricultural land was needed in all scenarios. Field emissions from the digestate used as organic fertilizer also had a significant impact on acidification and eutrophication. The choice of displaced marginal technologies has a huge influence on the results, as have the assumptions about the previous uses of the biogas plant inputs. The main finding emerging from this study was that the biogas plant should not use feedstock that is intended for animal feed because their replacement in animal diets involves additional impacts mostly in terms of extra agricultural land. cLCA appears to be a useful instrument for giving decision-makers information on the consequences of introducing new multifunctional systems such as farm-scale biogas plants, provided that the study uses specific local data and identifies displaced reference systems on a case-by-case basis.

Activity of antagonists in winter and early spring as well as in late summer and autumn plays an important role in the control of cereal aphid populations. Indeed, parasitoids active early in the year are important to avoid high aphid densities. Late summer and autumn correspond to the transition period between two wheat cultures, and parasitoid activity would thus reduce aphid infestation. During these critical periods, other crops like rye-grass and red clover containing alternative hosts could play the role of parasitoid reservoirs. During 1996, parasitoid activity was measured by trap planting in wheat, rye-grass, red clover and fallow grassland. In each plot, early spring was characterized by an important parasitoid activity, while aphids remained at a low level. Later in spring, activity decreased, and aphid development began even during this period. During the summer, when aphids reached their population peak, parasitoid activity rose again. Percentage of parasitism of aphids sampled was only important during summer in red clover and rye-grass. In wheat and fallow grassland, percentage of parasitism remained at a low level. The role of synchronization between parasitoid activity and aphid development is discussed.

International audience; Intensive livestock farming has raised issues about environmental impacts and food security during the past 20 years. As a consequence, there is a strong social demand for sustainable livestock systems. Sustainable livestock systems should indeed be environmentally friendly, economically viable for farmers, and socially acceptable, notably for animal welfare. For that goal, many sustainability indicators and methods have been developed at the farm level. The main challenge is using a transparent selection process to avoid assessment subjectivity. Here, we review typologies of sustainability indicators. We set guidelines for selecting indicators in a data-driven context, by reviewing selection criteria and discussing methodological issues. A case study is presented. The selected set of indicators mainly includes (1) environmental indicators focusing on farmer practices; (2) quantitative economic indicators; and (3) quantitative social indicators with a low degree of aggregation. The selection of indicators should consider (1) contextualization to determine purpose, scales, and stakeholders involved in the assessment; (2) the comparison of indicators based on various criteria, mainly data availability; and (3) the selection of a minimal, consistent, and sufficient set of indicators. Finally, we discuss the following issues: topics for which no indicators are measurable from available data should explicitly be mentioned in the results. A combination of means-based indicators could be used to assess a theme, but redundancy must be avoided. The unit used to express indicators influences the results and has therefore to be taken into account during interpretation. To compare farms from indicators, the influence of the structure on indicator values has to be carefully studied.

An optimal valorization of plant biomasses to produce biofuels requires a good knowledge of the available contents and molecular composition of the main chemical components, which changes with the harvesting date. Therefore, we assessed the influence of harvesting date on the chemical characteristics of various energy crops in the context of their conversion to biofuels.We showed that the biomass chemical composition, enzymatic digestible organic matter, bioethanol and thermal energy production potential for each species are impacted by the harvesting date. The proportion of enzymatically digestible organic matter decreases as the harvesting date is delayed. This is related to the increase in cellulose and lignin contents. The suitability of the biomasses for bioethanol production increases with harvest stage, as the total carbohydrates content increases. The suitability of the biomasses as a source of thermal energy increases according to the harvesting date as the proportion of organic matter increases and the content of mineral compounds decreases. For all investigated energy conversions, the best harvesting period is autumn, because the significantly higher crop dry matter yield largely compensates for the sometimes slightly less favorable chemical characteristics.While the biomass composition of energy crops changes with harvest stage, the dry biomass yield per unit area is the main factor that controls the total amount of chemical components, digestible organic matter, bioethanol and thermal energy that can be expected to be harvested per unit area. The biomass compositions presented in this paper are essential to investigate their suitability for bioenergy conversion.

Greenhouse gas emission intensity (GHGI; kilograms carbon dioxide equivalents/kilograms liveweight gain) have to be reduced so as to limit the impact of human activities on global warming while furnishing food to human. In this respect, performances of 654 Belgian Blue double-muscled bulls (BBdm) during their fattening phase were recorded. On this basis, their greenhouse gas emissions were modelled to estimate variation in GHGI and investigate mitigation options at that level. The relevance of theses option is discussed, taking into account the whole life and production system scales. Large variations (mean (s.d.)) were observed (from 7.2 (0.4) to 10.0 (0.7) kg carbon dioxide equivalents/kg liveweight gain) for, respectively, the 1st- and 4th-quantile groups defined for GHGI. Early culling, low liveweight and age at start of the fattening phase of the bulls would lead to a reduction of GHGI. Nevertheless, more than 32% of the variation remained unexplained. However, decision leading to reduction of GHG intensity at this stage of the life may be compensated in the early stage of BBdm. Attention is drawn on the necessity to encompass the whole life of BBdm for investigating mitigation options and on the sensitivity of the results on models and methodological choices.

Generalists and specialists use different cues to find their habitat and essential resources. While generalists have the advantage of exploiting a wider range of resources, they are predicted to be less efficient in using one particular resource compared to specialists. The level of specialization of parasitoids can be either at the habitat or at the host level; strategies used by either type are expected to differ. We examined interactions between three aphid parasitoid species that are a habitat specialist Aphidius rhopalosiphi, a habitat generalist Aphidius ervi, and a host generalist Praon volucre on three cereal aphids, Sitobion avenae, Metopolophium dirhodum and Rhopalosiphum padi. We compared total parasitism rate across behavioral and physiological variation in a non-choice test. Next, we addressed total parasitism in two phases to examine: (1) the response of parasitoids to different hosts through the behavioral sequence from antennation through oviposition, and (2) the physiological suitability of different hosts for oviposition and larval development. Parasitization typically involved the following behavioral steps: (1) antennal contact, (2) abdominal bending, and (3) ovipositor insertion (acceptance). A. rhopalosiphi had the same number of antennal contacts with the three aphids but showed fewer instances of abdominal bending towards R. padi. Pre-contact host preference was found for A. ervi but it did not correspond to the level of acceptance. The number of antennal contacts by P. volucre corresponded to the parasitization level of the aphid species but more mummies were produced on M. dirhodum than on R. padi. These results suggest that parasitoid species that are habitat specialists react similarly to the different host species present in the same habitat, whereas generalist species exhibit clear preferences during host selection. Preferences were, however, not always related to host suitability.

Biofuels can offer an alternative to fossil fuels in the context of climate change and fossil reserves depletion. Plant biomass consists mainly of structural (cell wall) polysaccharides, but contains also reserve polysaccharides (starch and polyfructans) and soluble sugars, that can be converted by micro-organisms. We examined the feasibility of a simple ethanol fermentation process directly from crude, not sterilized grasses with the commonly used yeast Saccharomyces cerevisae. Crude and steam- and/or polysaccharidase pretreated grass was fermented with S. cerevisiae for 40 hours at 40°C. Ethanol and volatile fatty acids were analyzed by GC-FID. The results show that S. cerevisae can produce ethanol directly from green herbaceous biomass with an ethanol concentration in the range 8–16 g(EthOH)/L without enzyme treatment. Polysaccharidase hydrolysis can increase the ethanol concentration by 20–100%. As crude, not sterilized substrate was used, the endogenous microbial flora was responsible for the production of lactic acid and other volatile fatty acids (mainly acetate and butyrate). The soluble sugar conversion to ethanol was 60–100% of the theorical yield. Enzymatic treatments did not increase significantly the availability of metabolizable sugars for S. cerevisiae. Grass harvest time had also no significant influence on ethanol production. Future work will focus on the characterization of the enzymatic hydrolysis and the release of soluble sugars.

Within the framework of the Optenerges project, funded under the Interreg IV program, the greenhouse gas (GHG) emissions of 62 cattle farms representative of the main production systems in the Province of Luxembourg in Wallonia, Belgium were assessed. The main goal of this study was to give reference values for GHG emission intensity in meat production systems based on grass (G) and on grass and maize (G-M). A second goal was to analyze emission variability in order to identify potential mitigation options. On average, for every kg live weight the G systems emitted 18.2 CO2 eq.. and the G-M systems 19.2 CO2 eq.. The difference reflected differences in feed and mineral fertilizer purchases, in manure emissions and in mineral fertilizer application. There were large variations in GHG emissions both between and within the two systems, particularly the latter. This variability was not due to the division of the farms into G and G-M systems, indeed production system types did not allow explaining the variation. When carbon credits were included in the assessment, there was an emission reduction of 31% and 23% for the G and G-M systems, respectively, indicating an opportunity for the systems using grassland to increase their advantage.

Temporal and spatial diversification of crops through rotation, multiple and intercropping schemes can improve farming systems efficiency, productivity and resilience, and thus sustainability. During recent years, farmers, scientists, advisors, private companies experienced crop diversification (CDE) all across Europe. These initiatives, how they are carried out and their outcomes, implies a wide diversity of parameters that are not easily taken into account by classical experimental approaches. During this conference, we propose a presentation of computer sciences tools developed for analyzing and visualizing data of various nature (qualitative, quantitative) collected to characterize european CDE.