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Background & aims: Roots are of paramount importance in protecting grassland in numerous ecosystem services e.g. soil organic matter build-up. However, studies that quantified root biomass in grasslands predominantly focused on areas managed less intensively than the management that is common to most North-West European grassland-based farms. To fill this knowledge gap, we compared, root and stubble biomass, the distribution in the soil and root diameter classes of five common European forage grass species grown under intensive management. Methods: On a 3 year old trial comparing yield of five cool season forage grass species at two N fertilization levels (190 kg N ha−1 yr−1 or 300 kg N ha−1 yr−1) we sampled root and stubble biomass until a depth of 90 cm deep. Results: Tall fescue (Festuca arundinacea) displayed the highest root and stubble biomass and had the highest mean root diameters of all studied grass species. The total dry biomass below cutting height (stubble + roots up to a depth of 90 cm below the soil surface) varied between 18 and 19 tonnes ha−1 for tall fescue and 10 and 11 tonnes ha−1 for Festulolium at 190 kg N ha−1 yr−1 and 300 kg N ha−1 yr−1, respectively. Conclusions: Our findings emphasize that in intensively managed grassland, root and stubble biomass under a 3 years old sward can be as high as 19 t DM ha−1. Owing to the high forage and root biomass of tall fescue, this species has a high potential in maintaining several ecosystem services

Performance and quality of tall fescue (Festuca arundinacea Schreb.) and perennial ryegrass (Lolium perenne L.) and mixtures of both species grown with or without white clover (Trifolium repens L.) under cutting management Abstract There is increasing interest in tall fescue (Festuca arundinacea Schreb.) in Western Europe and elsewhere, mainly because of its better drought resistance and yield potential compared with perennial ryegrass (Lolium perenne L.). Important drawbacks of tall fescue, compared with perennial ryegrass, are its lower digestibility and voluntary intake. Mixtures of both species might combine the advantages of each, and species interactions may eventually lead to transgressive overyielding. We compared the agronomic performance of tall fescue, perennial ryegrass and tall fescue-perennial ryegrass mixtures, as pure-grass swards or in association with white clover (Trifolium repens L.). Tall fescue-perennial ryegrass mixtures differed in the proportion and ploidy of the perennial ryegrass component. Yield, feed quality and botanical composition were measured in the 3 years after the sowing year. We found significant effects of ploidy of the ryegrass variety and of the proportion of ryegrass in the initial seed mixture on the botanical composition of the swards. Nevertheless, all swards were dominated by tall fescue at the end of the experiment. No overyielding of the mixtures compared with that of singlespecies swards was found, but feed quality was intermediate between that of the single-species swards. Mixed swards had better drought resistance than L. perenne and higher feeding quality than F. arundinacea swards.

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-Due to the growing cultivation area of genetically modified (GM) maize and the rising number of GM maize varieties commercially available to European farmers, the co-existence between GM and non-GM maize is becoming a burning issue in some European regions. Hence, Member States are imposing or discussing specific co-existence measures to keep the adventitious presence of GM material in non-GM produces below the established labelling threshold. As maize is a cross-pollinated crop that uses wind for the dispersal of its pollen, on-farm co-existence measures may rely on the spatial isolation of GM and non-GM maize fields. In this study, we developed an approach that combines geographic information system (GIS) datasets with Monte Carlo simulations to assess the feasibility of implementing isolation perimeters around GM maize fields, since its practical implementation is rarely addressed in the co-existence debate. More specifically, five scenarios differing in shares and spatial distributions of GM maize were tested for various isolation perimeters in two agricultural areas in Flanders (Belgium). The GIS analyses emphasised the small size of maize fields and their scattered distribution throughout the cropped area. The feasibility of implementing isolation perimeters was largely affected by the (GM) maize share, the spatial distribution of GM maize, and the width of isolation perimeters. The higher the (GM) maize share and the wider the isolation perimeter, the higher the proportions of farmers with non-GM maize fields occurring within the implemented isolation perimeter. Compared with randomly distributed GM maize fields, the clustering of GM maize fields on a larger scale and at the farm level increased the feasibility of implementing isolation perimeters. The approach developed proved to be a valuable tool to quantify the feasibility of implementing isolation perimeters under real agricultural conditions. adventitious mixing / co-existence / cross-fertilisation / genetically modified crops / geographic information system / isolation perimeters / pollen flow / regional variation / simulations

De Cauwer B, Van Den Berge K, Cougnon M, Bulcke R & Reheul D (2010). Weed seedbank responses to 12 years of applications of composts, animal slurries or mineral fertilisers. Weed Research50, 425–435. Summary Fertiliser amendments can impact weed populations in a variety of ways. This study evaluated the effects of 12‐year‐long applications of different fertilisation systems on size and composition of the weed seedbank in a conventionally managed maize monoculture field. Fertilisation systems included all factorial combinations of two dairy cattle slurry rates, three vegetable, fruit and garden waste compost rates, and three synthetic N fertiliser rates. Soil samples were taken in each subplot in May 2008 after sowing and prior to herbicide application. Residues recovered from soil samples were tested for weed seedling emergence to characterise soil seedbanks. Total weed seedbank density was affected by mineral N fertilisation, but not by compost or animal slurry application. Weed seedbank composition was related to compost amendment and mineral N fertilisation. Annual compost amendments reduced seedbank density of some persistent species (e.g., Chenopodium album and Solanum nigrum) irrespective of mineral N fertilisation. Compost is a promising tool for incorporation into integrated weed control strategies aimed at reducing weed seedbank persistence.

The persistence and productivity of forage grasses, important sources for feed production, are threatened by climate change-induced drought. Breeding programs are in search of new drought tolerant forage grass varieties, but those programs still rely on time-consuming and less consistent visual scoring by breeders. In this study, we evaluate whether Unmanned Aerial Vehicle (UAV) based remote sensing can complement or replace this visual breeder score. A field experiment was set up to test the drought tolerance of genotypes from three common forage types of two different species: Festuca arundinacea, diploid Lolium perenne and tetraploid Lolium perenne. Drought stress was imposed by using mobile rainout shelters. UAV flights with RGB and thermal sensors were conducted at five time points during the experiment. Visual-based indices from different colour spaces were selected that were closely correlated to the breeder score. Furthermore, several indices, in particular H and NDLab, from the HSV (Hue Saturation Value) and CIELab (Commission Internationale de l’éclairage) colour space, respectively, displayed a broad-sense heritability that was as high or higher than the visual breeder score, making these indices highly suited for high-throughput field phenotyping applications that can complement or even replace the breeder score. The thermal-based Crop Water Stress Index CWSI provided complementary information to visual-based indices, enabling the analysis of differences in ecophysiological mechanisms for coping with reduced water availability between species and ploidy levels. All species/types displayed variation in drought stress tolerance, which confirms that there is sufficient variation for selection within these groups of grasses. Our results confirmed the better drought tolerance potential of Festuca arundinacea, but also showed which Lolium perenne genotypes are more tolerant.