Sustainability of European winter wheat- and maize-based cropping systems: Economic, environmental and social ex-post assessment of conventional and IPM-based systems

In order to ensure higher sustainability of winter wheat and maize production in Europe, cropping systems featuring different levels of Integrated Pest Management (IPM) need to be tested in the field and validated for their sustainability before being adopted by farmers. However, the sustainability evaluation of cropping systems is difficult to perform effectively due to the complex economic, social and environmental dimensions of sustainability. Within the EU research project PURE, nine long-term experiments were conducted in various European regions from 2011 to 2014, comparing two IPM levels against the conventional system (CS) in winter wheat- and maize-based cropping systems. IPM1 encompassed some pesticide use in semi-diverse crop rotations while IPM2 favoured reduced- and non-chemical methods in diverse rotations. The modified DEXiPM (DEXi Pest Management) model for arable cropping systems was used for ex-post assessments to compare the economic, environmental and social sustainability of these systems. The assessments showed that in six out of nine trials the CS was overall unsustainable because of low evaluation of the environmental sustainability that was mainly due to high pesticide use and simplified crop rotations where the choice of crops is primarily market-driven. In contrast, six IPM1 and five IPM2 systems could be classified as sustainable, achieving ‘medium’ or ‘high’ scores for all three sustainability dimensions. Differences in the socio-economic conditions across countries and/or climatic and soil conditions across experimental trials highlighted that IPM is based on general principles that must be adapted to address specific local conditions. Overall, IPM systems included more diverse crop rotations and practices compared to the CS, promoting IPM-based strategies with less pesticide use but also a reduced reliance on pesticides that could partially compensate for any yield reductions by the savings on pesticide and application costs. It is recommended that the results of the study should be disseminated to policy-makers, advisors and farmers and that their implementation should be considered on a regional level. Regional policies to encourage the adoption of more sustainable systems based on IPM principles, as well as better support by more closely involving the regional advisory services for the general implementation of IPM is further recommended. Ex-post analysis with DEXiPM also identified the constraints of the IPM1 and IPM2 systems evaluated as not sustainable. These were related to i) environmental issues for those IPM1 systems that still relied mainly on pesticide use and had less diverse crop rotations, and ii) economic issues for IPM2 systems, mainly due to the choice of less profitable crops in the rotation, as well as to yield penalties caused by the very low pesticide use or replacing pesticides with less effective non-chemical methods. The identification of these constraints is a valuable input to the local and regional discussion on how to adopt IPM and develop more sustainable cropping systems

Stocker du carbone dans les sols agricoles : évaluation de leviers d’action pour la France

Ce numéro d'Innovations Agronomiques comprend les articles correspondant aux présentations du colloque « Atténuation des Gaz à Effet de Serre par l’agriculture » qui s'est tenu à Versailles le 4 juin 2014.Soils contain very large stocks of carbon as organic matter. We identified agricultural practices that would increase soil C stocks, without major changes in the cropping systems. We considered four actions: reduced tillage, plant more cover crops in annual cropping systems, develop agroforestry and hedges, and manage grasslands to store soil C. We quantified the additional soil C storage potential per unit surface area, the applicability of the actions in mainland France and their C storage potential at the national scale. The results suggest that to store additional C in soils, it would be more efficient to increase organic matter inputs by planting trees and replacing bare soil by cover crops, rather than by attempting to reduce organic matter mineralization reducing or eliminating tillage. This work is part of a larger study comparing technical levers to reduce greenhouse gas emissions from agriculture in mainland France.Les sols contiennent une très grande quantité de carbone, sous forme de matières organiques. Nous avons identifié des pratiques agricoles qui permettraient, sans changement majeur du système de production, d’accroître les stocks de carbone des sols. Nous avons instruit quatre actions : la réduction du travail du sol, l’implantation de davantage de couverts dans les systèmes de culture, le développement de l’agroforesterie et des haies et l’optimisation de la gestion des prairies. Nous décrivons ici ces actions, leur potentiel de stockage de C additionnel par unité de surface, l’assiette sur laquelle elles pourraient être développées et leur potentiel de stockage à l’échelle nationale. Les résultats montrent qu’il apparaît plus efficace, en termes de stockage de C dans le sol, d’accroître les entrées de matière organique au sol, par implantation de ligneux en association ou en remplacement de sols nus, par des couverts végétaux, plutôt que de tenter de réduire les vitesses de minéralisation des matières organiques par des pratiques de non labour. Ce travail s’intègre dans une étude plus vaste de comparaison de leviers techniques pour limiter les émissions de gaz à effet de serre en agriculture

Stocker du carbone dans les sols agricoles : évaluation de leviers d’action pour la France

Ce numéro d'Innovations Agronomiques comprend les articles correspondant aux présentations du colloque « Atténuation des Gaz à Effet de Serre par l’agriculture » qui s'est tenu à Versailles le 4 juin 2014.Soils contain very large stocks of carbon as organic matter. We identified agricultural practices that would increase soil C stocks, without major changes in the cropping systems. We considered four actions: reduced tillage, plant more cover crops in annual cropping systems, develop agroforestry and hedges, and manage grasslands to store soil C. We quantified the additional soil C storage potential per unit surface area, the applicability of the actions in mainland France and their C storage potential at the national scale. The results suggest that to store additional C in soils, it would be more efficient to increase organic matter inputs by planting trees and replacing bare soil by cover crops, rather than by attempting to reduce organic matter mineralization reducing or eliminating tillage. This work is part of a larger study comparing technical levers to reduce greenhouse gas emissions from agriculture in mainland France.Les sols contiennent une très grande quantité de carbone, sous forme de matières organiques. Nous avons identifié des pratiques agricoles qui permettraient, sans changement majeur du système de production, d’accroître les stocks de carbone des sols. Nous avons instruit quatre actions : la réduction du travail du sol, l’implantation de davantage de couverts dans les systèmes de culture, le développement de l’agroforesterie et des haies et l’optimisation de la gestion des prairies. Nous décrivons ici ces actions, leur potentiel de stockage de C additionnel par unité de surface, l’assiette sur laquelle elles pourraient être développées et leur potentiel de stockage à l’échelle nationale. Les résultats montrent qu’il apparaît plus efficace, en termes de stockage de C dans le sol, d’accroître les entrées de matière organique au sol, par implantation de ligneux en association ou en remplacement de sols nus, par des couverts végétaux, plutôt que de tenter de réduire les vitesses de minéralisation des matières organiques par des pratiques de non labour. Ce travail s’intègre dans une étude plus vaste de comparaison de leviers techniques pour limiter les émissions de gaz à effet de serre en agriculture

Field testing of IPM-based cropping systems: a diversity of experimental approaches in Europe

International audienceIntegrated Pest Management (IPM) emphasizes physical and biological regulation strategies to control pests while reducing the reliance on pesticides. It is often based on combinations of control measures, because each available alternative measure might have a moderate efficiency. Field experiments are required to analyse the interactions between control measures, and to evaluate the sustainability of IPM-based cropping systems (CS). A network of European agronomists managing field experiments at the CS level was set recently, aiming at sharing data and expertise to enhance our knowledge on IPM. Comparing methodologies highlighted a diversity of approaches in CS design and experimental layouts. This diversity is partly related with the research context and objectives. Some experiments intend to explore really innovative strategies and gain scientific knowledge about how such innovative CS behave, while others aim at providing quickly adoptable solutions for local farmers. In some research programs, the experiment is part of the CS design process, and tested CS are regularly revised, while in other cases CS are kept stable across years so as to be able to evaluate cumulative long term effects. The concept of CS itself is viewed differently across scientists, and this affects protocols: some consider each CS as a sequence of techniques, which has to be similar across repetitions, others define a CS as a set of decision-making rules that allows a flexibility in the actual sequences of techniques. The main difference among experiments differentiates factorial layouts from systemic approaches: factorial experiments make it possible to quantify the effects of each IPM factor, and to analyse the interactions, without particular attention for the consistency among components constituting each CS. On the contrary, system approach focuses on the overall evaluation of CS designed with a great attention paid to their consistency, hence maximizing the chance to meet the system objectives (in the case of IPM, to use little amount of pesticide while maintaining the CS sustainability). Such field experiments are costly, so preliminary reflections defining the experimental strategy have a critical importance. Networking at the European level may constitute a useful exchange platform with potential scientific added value