• Energy Research

AbstractConversion of semi-natural habitats, such as field margins, fallows, hedgerows, grassland, woodlots and forests, to agricultural land could increase agricultural production and help meet rising global food demand. Yet, the extent to which such habitat loss would impact biodiversity and wild species is unknown. Here we survey species richness for four taxa (vascular plants, earthworms, spiders, wild bees) and agricultural yield across a range of arable, grassland, mixed, horticulture, permanent crop, for organic and non-organic agricultural land on 169 farms across 10 European regions. We find that semi-natural habitats currently constitute 23% of land area with 49% of species unique to these habitats. We estimate that conversion of semi-natural land that achieves a 10% increase in agricultural production will have the greatest impact on biodiversity in arable systems and the least impact in grassland systems, with organic practices having better species retention than non-organic practices. Our findings will help inform sustainable agricultural development.

Planting and destruction are the two main phases in cover crop management techniques. Their dates and implementation conditions play a key role in terms of the various functions targeted for these crops (nitrate-trapping, erosion prevention, weed control, effect on next crop, etc.). The analysis of the literature therefore focused on cover crop planting and destruction techniques. The aim was to identify the different methods and, if possible, their effectiveness with respect to the success of sowing and destruction. The issue of the implementation of these techniques by farmers was then examined by analysing the constraints in terms of organization of labour and implementation costs.

Plants perform in a specific Eh–pH spectrum and they rely on various processes to ensure their homeostasis, which plays a central role in their defense. The effects of multiple stresses, all translated into oxidative stress into the plant, and the capacity of the latter to respond to these stresses results in specific Eh–pH states in plants. We reviewed plant-invertebrate pests and plant-pathogens interactions under a Eh–pH homeostasis perspective by extensively analyzing the literature, which converges and supports a set of hypotheses. We report examples showing how the development and attacks of pests are correlated to spatio-temporal variations of Eh–pH in plants. We provide evidence-based discussion on how Eh–pH homeostasis can open a new perspective on plant health, and help unravel and disentangle the many Genotype x Environment x Management x Pest and Pathogen interactions. We propose an original perspective on energy allocation and growth-defense tradeoff by plants based on the Eh–pH homeostasis model. Finally, we show how Eh–pH conditions in the rhizosphere are the results of multiple interactions between the root system and microorganisms. Based on this, we hypothesize that soil suppressiveness is derived from soil structure leading to diverse Eh–pH niches that harbor a diversity of microorganisms. The Eh–pH homeostasis model proposed herein is central to soil and plant health. An Eh–pH perspective could become a very powerful tool to develop a “one health approach” unifying a large range of bio-physical processes in a very coherent and consistent manner.

Life Cycle Assessment (LCA) is a widely used tool to assess environmental sustainability of products. The LCA should optimally cover the most important environmental impact categories such as climate change, eutrophication and biodiversity. However, impacts on biodiversity are seldom included in LCAs due to methodological limitations and lack of appropriate characterization factors. When assessing organic agricultural products the omission of biodiversity in LCA is problematic, because organic systems are characterized by higher species richness at field level compared to the conventional systems. Thus, there is a need for characterization factors to estimate land use impacts on biodiversity in life cycle assessment that are able to distinguish between organic and conventional agricultural land use that can be used to supplement and validate the few currently suggested characterization factors. Based on a unique dataset derived from field recording of plant species diversity in farmland across six European countries, the present study provides new midpoint occupation Characterization Factors (CF) expressing the Potentially Disappeared Fraction (PDF) to estimate land use impacts on biodiversity in the 'Temperate Broadleaf and Mixed Forest' biome in Europe. The method is based on calculation of plant species on randomly selected test sites in the biome and enables the calculation of characterization factors that are sensitive to particular types of management. While species richness differs between countries, the calculated CFs are able to distinguish between different land use types (pastures (monocotyledons or mixed), arable land and hedges) and management practices (organic or conventional production systems) across countries. The new occupation CFs can be used to supplement or validate the few current CF's and can be applied in LCAs of agricultural products to assess land use impacts on species richness in the 'Temperate Broadleaf and Mixed Forest' biome.