A method to search for optimal field allocations of transgenic maize in the context of co-existence

Spatially isolating genetically modified (GM) maize fields from non-GM maize fields is a robust on-farm measure to keep the adventitious presence of GM material in the harvest of neighboring fields due to cross-fertilizations below the European labeling threshold of 0.9%. However, the implementation of mandatory and rigid isolation perimeters can affect the farmers' freedom of choice to grow GM maize on their fields if neighboring farmers do not concur with their respective cropping intentions and crop plans. To minimize the presence of non-GM maize within isolation perimeters implemented around GM maize fields, a method was developed for optimally allocating GM maize to a particular set of fields. Using a Geographic Information System dataset and Monte Carlo analyses, three scenarios were tested in a maize cultivation area with a low maize share in Flanders (Belgium). It was assumed that some farmers would act in collaboration by sharing the allocation of all their arable land for the cultivation of GM maize. From the large number of possible allocations of GM maize to any field of the shared pool of arable land, the best field combinations were selected. Compared to a random allocation of GM maize, the best field combinations made it possible to reduce spatial co-existence problems, since at least two times less non-GM maize fields and their corresponding farmers occurred within the implemented isolation perimeters. In the selected field sets, the mean field size was always larger than the mean field size of the common pool of arable land. These preliminary data confirm that the optimal allocation of GM maize over the landscape might theoretically be a valuable option to facilitate the implementation of rigid isolation perimeters imposed by law.

Statistical modelling of nitrogen use efficiency of dairy farms in Flanders

In the past decade it has repeatedly been shown that agriculture is a significant source of ground-and surface water pollution. Nitrogen losses and nitrogen use efficiency (NUE) are major concerns in agricultural practice and of policy-makers. Rapid intensification of livestock production, a result of the focus on increasing productivity from the 1950s onwards, has contributed to a large increase in nutrient surpluses. Here, we performed a quantitative analysis of the variables influencing the nitrogen use efficiency in Flemish grassland-based farming systems. The analysis was based on the large dataset of the Farm Accountancy Data Network, holding technical and economic data of Flemish farms. A statistical model is proposed by performing multiple regression with several variable selection procedures. Many combinations of variables were studied in 92 models and different criteria were taken into account to select the most adequate combination of variables. This approach focuses on a deep statistical analysis and interpretation of the model. The novelty of this research is the quantification and comparison of the influence of different inputs and other variables in nitrogen use efficiency at the farm level. Our results show that, contrary to current knowledge, a higher nitrogen use efficiency was observed for farms with a higher number of 'Dairy cows ha(-1)', holding the rest of the N inputs constant. A higher stocking density is compatible with a higher agricultural sustainability. It is demonstrated that the amount of milk N produced by added cows is higher than the decrease in milk N produced by each single cow due to a reduced input of feed N per cow. The dairy cow becomes more efficient in the use of N, increasing the farm-gate NUE and the farm sustainability. In the dataset of this study, the variable 'Dairy cows ha(-1)' is more relevant than suggested by previous studies: 1.4 times more relevant than the variable 'kg of N in fertilisers ha(-1)', which is 1.5 times more relevant than 'kg of N in concentrates ha(-1)'. According to previous knowledge, the N input variables present a negative sign. Decreasing the N input in fertilisers, concentrates and by-products are recommended actions to increase the NUE. Unexpected interaction effects were found

Using an oilseed rape x wild/weedy relative gene flow index for the monitoring of transgenic oilseed rape

To estimate the introgressive hybridisation propensity (IHP) between transgenic oilseed rape and certain of its cross-compatible wild/weedy relatives at the landscape level, a conceptual approach was developed. A questionnaire was established enclosing the successive steps to successfully achieve introgressive hybridisation. Each step was described and scored, resulting in an IHP value for each cross-compatible wild/weedy relative. This approach revealed that in Flanders (Belgium) Brassica rapa has the highest IHP value, followed by Hirschfeldia incana, Diplotaxis tenuifolia, Raphanus raphanistrum and Sinapis arvensis. Using these values, monitoring priorities can be defined within the pool of cross-compatible wild/weedy oilseed rape relatives. It is discussed how the numerical quantification may serve as a valuable tool in case-specific monitoring and general surveillance of transgenic oilseed rape

The interplay between societal concerns and the regulatory frame on GM crops in the European Union

Recapitulating how genetic modification technology and its agro-food products aroused strong societal opposition in the European Union, this paper demonstrates how this opposition contributed to shape the European regulatory frame on GM crops. More specifically, it describes how this opposition contributed to a de facto moratorium on the commercialization of new GM crop events in the end of the nineties. From this period onwards, the regulatory frame has been continuously revised in order to slow down further erosion of public and market confidence. Various scientific and technical reforms were made to meet societal concerns relating to the safety of GM crops. In this context, the precautionary principle, environmental post-market monitoring and traceability were adopted as ways to cope with scientific uncertainties. Labeling, traceability, co-existence and public information were installed in an attempt to meet the general public request for more information about GM agro-food products, and the specific demand to respect the consumers' and farmers' freedom of choice. Despite these efforts, today, the explicit role of public participation and/or ethical consultation during authorization procedures is at best minimal. Moreover, no legal room was created to progress to an integral sustainability evaluation during market procedures. It remains to be seen whether the recent policy shift towards greater transparency about value judgments, plural viewpoints and scientific uncertainties will be one step forward in integrating ethical concerns more explicitly in risk analysis. As such, the regulatory frame stands open for further interpretation, reflecting in various degrees a continued interplay with societal concerns relating to GM agro-food products. In this regard, both societal concerns and diversely interpreted regulatory criteria can be inferred as signaling a request – and even a quest – to render more explicit the broader-than-scientific dimension of the actual risk analysis

Impact of the quality of organic amendments on size and composition of the weed seed bank

In addition to improving the soil quality, organic amendments of soils may affect weed seed survival, emergence, growth and reproduction. This study evaluated the effects of applications of different qualities of organic amendments on size and composition of the weed seed bank in a field under sequential cropping over 4 years. Fertilisation systems tested included farmyard manure, vegetable fruit and garden waste compost, two types of farm compost differing in carbon:nitrogen (C:N) ratio, cattle slurry and mineral fertiliser. All organically amended plots received equal amounts of C. Crop growth was equalised on all plots by applying supplemental mineral N. Seed bank sampling took place in May 2009 to a depth of 10 cm. The weed seed bank was analysed using the seedling emergence method. Despite equal crop growth in fertilised plots, total seed bank density was lowest in plots amended with compost with low C:N ratio and highest in slurry-amended plots. Observed differences in seed bank densities reflected differences in soil organic carbon content and microbial biomass. At plot level, hard-coated seeds in the seed bank (e.g. Chenopodium spp.) were inversely related to soil microbial activity. Observed differential responses of species to applied fertilisers might be attributed to interspecific differences in resistance against microbial seed degradation. Compost-based fertilisation systems could be sustainable tools for incorporation into integrated weed control strategies aiming at depleting the weed seed bank

Differential sensitivity of locally naturalized Panicum species to HPPD- and ALS-inhibiting herbicides

Panicum schinzii (Transvaal millet), P. dichotomiflorum (Fall panicum) and P. capillare (Witchgrass) are alien panicoid grasses that have gradually spread and are now locally naturalized in corn fields in Belgium. One of the possible reasons for their expansion in corn fields might be a lower sensitivity to post-emergence herbicides acting against panicoid grasses, in particular those inhibiting 4-hydroxyphenyl pyruvate dioxygenase (HPPD) and acetolactate synthase (ALS). Dose-response pot experiments were conducted in the greenhouse to evaluate the effectiveness of five HP-PD-inhibiting herbicides (sulcotrione, mesotrione, isoxaflutole, topramezone, tembotrione) and two AILS-inhibiting herbicides (nicosulfuron, foramsulfuron) for controlling populations of P. schinzii, P. dichotomiflorum and P. capillare (all naturalized Belgian populations except for P. capillare). In another dose-response pot experiment, sensitivity of five local P. dichotomiflorum populations to HPPD-inhibitors and nicosulfuron was investigated. Finally, the influence of growth stage at time of herbicide application on efficacy of topramezone and nicosulfuron for Panicum control was evaluated. Large interspecific differences in sensitivity to HPPD-inhibiting herbicides were observed. Panicum schinzii was sensitive to tembotrione but moderately sensitive to topramezone and poorly sensitive to mesotrione and sulcotrione. However, P. dichotomiflorum was sensitive to mesotrione and topramezone but moderately sensitive to tembotrione. All Panicum species were sensitive to low doses of nicosulfuron and foramsulfuron. Naturalized P. dichotomiflorum populations exhibited differential herbicide sensitivity profiles. All species tested showed a progressive decrease in sensitivity to topramezone and nicosulfuron with seedling age. A satisfactory post-emergence control of Panicum species in the field will require appropriate choice of herbicide and dose, as well as a more timely application (i.e. before weeds reach the four leaves stage)