Mathias Cougnon

Environmental impact of herbicide regimes used with genetically modified herbicide-resistant maize

With the potential advent of genetically modified herbicide-resistant (GMHR) crops in the European Union, changes in patterns of herbicide use are predicted. Broad-spectrum, non-selective herbicides used with GMHR crops are expected to substitute for a set of currently used herbicides, which might alter the agro-environmental footprint from crop production. To test this hypothesis, the environmental impact of various herbicide regimes currently used with non-GMHR maize in Belgium was calculated and compared with that of possible herbicide regimes applied in GMHR maize. Impacts on human health and the environment were calculated through the pesticide occupational and environmental risk (POCER) indicator. Results showed that the environmental impact of herbicide regimes solely relying on the active ingredients glyphosate (GLY) or glufosinate-ammonium (GLU) is lower than that of herbicide regimes applied in non-GMHR maize. Due to the lower potential of GLY and GLU to contaminate ground water and their lower acute toxicity to aquatic organisms, the POCER exceedence factor values for the environment were reduced approximately by a sixth when GLY or GLU is used alone. However, the environmental impact of novel herbicide regimes tested may be underestimated due to the assumption that active ingredients used with GMHR maize would be used alone. Data retrieved from literature suggest that weed control efficacy is increased and resistance development delayed when GLY or GLU is used together with other herbicides in the GMHR system. Due to the partial instead of complete replacement of currently used herbicide regimes, the beneficial environmental impact of novel herbicide regimes might sometimes be reduced or counterbalanced. Despite the high weed control efficacy provided by the biotechnology-based weed management strategy, neither indirect harmful effects on farmland biodiversity through losses in food resources and shelter, nor shifts in weed communities have been demonstrated in GMHR maize yet. However, with the increasing adoption rate of GMHR maize and their associated novel herbicide regimes, this situation is expected to change in the short-term.

Feasibility of isolation perimeters for genetically modified maize

Using geographic information system datasets and Monte Carlo simulations, this study investigates to what extent the intra-regional variability in maize share and field distribution affects the feasibility of implementing isolation perimeters between genetically modified (GM) and non-GM maize fields. More specifically, five scenarios differing in shares and spatial distributions of GM maize were tested for various isolation perimeters in six agricultural areas in Flanders (Belgium). Proportions of non-GM maize fields and farmers having at least one non-GM maize field occurring within isolation perimeters were calculated to assess how spatial co-existence measures would affect the freedom of choice of neighbouring farmers to grow non-GM maize on their fields. Irrespective of the scenario tested, our results demonstrated that the proportions of non-GM maize fields and their corresponding farmers falling within the isolation perimeters are approximately two to eight times higher in areas with the highest maize share than in areas with the lowest maize share. The higher the share of GM maize and the wider the imposed isolation perimeter, the lower the intra-regional differences became. Hence, those findings confirm that farmers will not be equally affected by isolation perimeters, indicating the importance of considering intra-regional differences in the choice of appropriate spatial co-existence measures. Since uniform and wide isolation perimeters tend to be difficult to implement in practice and hardly reflect the diversity of the agricultural landscape, relying on flexible or combining various co-existence measures is worthwhile considering. As an alternative to single co-existence measures for limiting the GM input from cross-fertilisations between neighbouring maize fields, the appropriateness of other on-farm co-existence measures is discussed for Flemish agricultural conditions. Proposing the most appropriate co-existence measures on a case-by-case basis may be one step forward in reaching proportionate, fair and consistent co-existence at the regional and landscape level.

The Role of Forage Crops in Multifunctional Agriculture

UNESCO defines grassland as “land covered with herbaceous plants with less than 10 percent tree and shrub cover”. In many cases, grassland is grazing land.

Factors Influencing Animal Preference of Tall Fescue Genotypes

An important disadvantage of tall fescue (Festuca arundinacea Schreb.) is its low voluntary intake, resulting in low performances under a grazing management. Our breeding objective was to relate animal preference with leaf morphology and mechanical characteristics. Sixteen different clones were selected from a breeding programme and cloned to be planted in mini swards grazed by sheep and rabbits. In 2012 we measured leaf blade length, width, shear breaking load, shear strength, pre-grazing sward height, leaf harshness, dry matter content and rumen degraded organic matter. Leaf harshness, pre-grazing sward height and rabbit preference were the best estimators for sheep preference.

What Global and/or European Agriculture Will Need from Grasslands and Grassland Breeding over the Next 10–15 Years for a Sustainable Agriculture

The paper analyses actual trends in (European) ruminant agriculture and grassland based production systems. Consequences of reduced and/or zero grazing for grass breeding and grassland management are discussed. The impacts on eco-efficiency, recycling of minerals and ecosystem services are highlighted as well as the role of ley-arable farming. Special emphasis is on the potential use of tall fescue as a component of mixtures or as an interspecific cross. In grazed grassland, the role of white clover, the disease resistance and the nitrogen use efficiency of the grasses and the significance of biodiversity are considered. Based on an article published by Parsons et al. (2011) some reflections on the way ahead in grass and forage breeding are presented.

NIRS Calibration Strategies for the Botanical Composition of Grass-Clover Mixtures

In literature, different calibrations to predict the species composition of grass legumes mixtures or mixtures of different grass species are described. Mostly, these calibrations were developed using so called “artificial samples”. These artificial samples are obtained by mixing pure (ground) material of the species for which the calibration is developed in known proportions. The plant material used for these artificial samples may have been grown in mixtures or in pure stands. Calibrations based on artificial samples mostly have very good calibration statistics but fail to predict real validation samples. “Real samples” are obtained by hand separation of species mixtures into the different species followed by recomposition. The advantage of the use of artificial samples relative to real samples is that a lot of calibration samples with a different composition can be obtained with a relative small labour input. We built calibrations to predict the white clover content in grass clover mixtures, based on real and artificial samples with the same composition, and validated them with the same independent samples. Calibrations based on real samples performed far better than calibrations based on artificial samples. The failure of the latter can be explained by the lack of environmental variation in their spectra. We recommend a calibration strategy based on fewer but more diverse hand sorted samples, rather than making a lot of artificial samples that contain relatively little spectral information.

Biological Flora of the British Isles : Milium effusum

1. This account presents information on all aspects of the biology of Milium effusum L. (Wood Millet) that are relevant to understanding its ecological characteristics and behaviour. The main topic ...

Morpho-physiological responses to dehydration stress of perennial ryegrass and tall fescue genotypes

Worldwide drought stress is the most important restriction factor on food and fodder productivity. In this study, morpho-physiological adaptations to dehydration stress were investigated in two tall fescue (Festuca arundinacea Schreb.) genotypes (Fa13 and Fa19 with a high and low sheep grazing preference respectively) and Lolium perenne L. Drought stress as evaluated by decreasing stomatal conductance and chlorophyll content, chlorophyll fluorescence parameters and fructan concentration were first observed in L. perenne (16 days after the start of the drought stress). Furthermore, after 20 days of drought stress the activities of ascorbate peroxide (APX), catalase (CAT), and superoxide dismutase (SOD) were reduced in stressed plants indicating that the capacity to scavenge ROS diminished under severe stress though no differences between genotypes were observed. Osmotic adjustment by carbohydrates did also not differ between the genotypes. Proline, however, reached its highest level in drought-stressed L. perenne followed by Fa13 and Fa19 respectively. The studied species showed a similar degree in response in the traits assessed when plants were exposed to dehydration stress; however changes were first observed in L. perenne.

Silica Content, Leaf Softness and Digestibility in Tall Fescue (Festuca arundinacea Schreb.)

In tall fescue breeding, a great deal of effort is devoted to develop soft-leaved varieties as it is generally accepted that leaf softness is positively correlated with digestibility and animal preference. In advanced breeding programs, it becomes difficult to discriminate the leaf softness between genotypes. Moreover, there is evidence that the digestibility of the softest varieties is not necessarily higher compared to varieties with coarser leaves. We studied the presence of trichomes (dentation) on the leaf margins and the silica content of plants in relation to the leaf softness and digestibility on a selection of 19 tall fescue clones. On average, soft genotypes had fewer trichomes (2.74 mm−1) on the leaf margins than coarse genotypes (9.03 mm−1), but there was no relation between leaf softness or trichome number and digestibility (R2 = 0.05), nor between silica content and softness or digestibility (R2 = 0.09).

The Sense of Testing Sheep Preference in Tall Fescue Variety Evaluation

Tall fescue (Festuca arundinacea Schreb.) has a low digestibility and a low intake when grazed compared to ryegrasses. To make progress in these traits, we introduced a new way of testing candidate varieties (candivars) in our breeding program. We ran simultaneously a yield trial, in which yield and digestibility were measured, and a preference trial where sheep preference was evaluated using two methods: a qualitative (visual) and a quantitative measurement. In this paper we question whether such a preference test has an added value. Based on results of 18 candivars, we conclude that measuring sheep preference makes sense, because not all varieties with a high digestibility have good preference.