A.C. Moonen

Field margins in northern Europe: their functions and interactions with agriculture

Abstract Most agricultural landscapes are a mosaic of farmers’ fields, semi-natural habitats, human infrastructures (e.g. roads) and occasional natural habitats. Within such landscapes, linear semi-natural habitats often define the edges of agricultural fields. This paper reviews the role and interactions within and between the flora of these elements. In temperate, intensive agriculture, such field margin habitats, which historically had true agricultural functions, now are important refugia for biodiversity. As manmade habitats, field margins may also have important cultural roles as part of our landscape heritage, e.g. hedges in Britain. Whilst field margins are not usually specific habitat types, they contain a variety of plant communities in a variety of structures. These may range from aquatic elements to ruderal and woodland communities. Studies demonstrate a variety of interactions between fields and their margins. Agricultural operations, such as fertiliser and pesticide application, have effects on the flora. Some margin flora may spread into crops, becoming field weeds. Margins also have a range of associated fauna, some of which may be pest species, while many are beneficial, either as crop pollinators or as pest predators. The biodiversity of the margin may be of particular importance for the maintenance of species at higher trophic levels, notably farmland birds, at the landscape scale. Margins contribute to the sustainability of production, by enhancing beneficial species within crops and reducing pesticide use. In northwestern Europe, a variety of methods to enhance diversity at field edges have been introduced, including sown grass and flower strips. The impact of these on weed flora and arthropods indicate mostly beneficial effects though conflicts exist, notably for the conservation of rare arable weed species.

Climate change in Italy indicated by agrometeorological indices over 122 years

To determine the risk of climate change for agriculture it is necessary to define a set of agrometeorological parameters, derived from the classic climate parameters, that are capable of indicating the consequences of climate change for crop production. In this study high-quality daily rainfall, evaporation and mean, minimum and maximum temperature data collected since 1878 at the meteorological station of the Department of Agronomy and Agroecosystem Management of the University of Pisa, Italy (H = 6 m a.s.l.; latitude = 43 ◦ 41 � N; longitude = 10 ◦ 23 � E) were used to calculate extreme temperature and rainfall events, frost risk, flooding risk and drought risk. Time trends for all variables were analysed using linear regression techniques. Results indicate that the changes in extreme events in Pisa have not changed in a way that is likely to negatively affect crop production. The risk of crop damage due to frost has decreased and sowing time in spring can safely be anticipated. The soil moisture surplus (SMS) and theoretical irrigation requirement (TIR) have not changed despite a decreasing rainfall trend. The number of soil moisture surplus days in autumn has decreased indicating a decrease in flooding risk, which can have a positive effect on soil workability.

Eight principles of integrated pest management

The use of pesticides made it possible to increase yields, simplify cropping systems, and forego more complicated crop protection strategies. Over-reliance on chemical control, however, is associated with contamination of ecosystems and undesirable health effects. The future of crop production is now also threatened by emergence of pest resistance and declining availability of active substances. There is therefore a need to design cropping systems less dependent on synthetic pesticides. Consequently, the European Union requires the application of eight principles (P) of Integrated Pest Management that fit within sustainable farm management. Here, we propose to farmers, advisors, and researchers a dynamic and flexible approach that accounts for the diversity of farming situations and the complexities of agroecosystems and that can improve the resilience of cropping systems and our capacity to adapt crop protection to local realities. For each principle (P), we suggest that (P1) the design of inherently robust cropping systems using a combination of agronomic levers is key to prevention. (P2) Local availability of monitoring, warning, and forecasting systems is a reality to contend with. (P3) The decision-making process can integrate cropping system factors to develop longer-term strategies. (P4) The combination of non-chemical methods that may be individually less efficient than pesticides can generate valuable synergies. (P5) Development of new biological agents and products and the use of existing databases offer options for the selection of products minimizing impact on health, the environment, and biological regulation of pests. (P6) Reduced pesticide use can be effectively combined with other tactics. (P7) Addressing the root causes of pesticide resistance is the best way to find sustainable crop protection solutions. And (P8) integration of multi-season effects and trade-offs in evaluation criteria will help develop sustainable solutions.

Landscape agronomy: a new field for addressing agricultural landscape dynamics

Landscape dynamics increasingly challenge agronomists to explain how and why agricultural landscapes are designed and managed by farmers. Nevertheless, agronomy is rarely included in the wide range of disciplines involved in landscape research. In this paper, we describe how landscape agronomy can help explain the relationship between farming systems and agricultural landscape dynamics. For this, we propose a conceptual model of agricultural landscape dynamics that illustrates the specific contribution of agronomy to landscape research. This model describes the relationship between three elements: farming practices, landscape patterns and natural resources. It can stimulate agronomists to deal with research issues in agricultural landscape dynamics and enhance the interdisciplinary integration of farming systems in wider landscape research. On these premises, we discuss the main research issues that will benefit from an active involvement of agronomy, to understand, but also to assess landscape dynamics and to design relevant decision support systems.

Structure, function and management of semi-natural habitats for conservation biological control : A review of European studies

Different semi-natural habitats occur on farmland, and it is the vegetations traits and structure that subsequently determine their ability to support natural enemies and their associated contribution to conservation biocontrol. New habitats can be created and existing ones improved with agri-environment scheme funding in all EU member states. Understanding the contribution of each habitat type can aid the development of conservation control strategies. Here we review the extent to which the predominant habitat types in Europe support natural enemies, whether this results in enhanced natural enemy densities in the adjacent crop and whether this leads to reduced pest densities. Considerable variation exists in the available information for the different habitat types and trophic levels. Natural enemies within each habitat were the most studied, with less information on whether they were enhanced in adjacent fields, while their impact on pests was rarely investigated. Most information was available for woody and herbaceous linear habitats, yet not for woodland which can be the most common semi-natural habitat in many regions. While the management and design of habitats offer potential to stimulate conservation biocontrol, we also identified knowledge gaps. A better understanding of the relationship between resource availability and arthropod communities across habitat types, the spatiotemporal distribution of resources in the landscape and interactions with other factors that play a role in pest regulation could contribute to an informed management of semi-natural habitats for biocontrol.

Augmenting flower trait diversity in wildflower strips to optimise the conservation of arthropod functional groups for multiple agroecosystem services

AbstractSown wildflower strips are increasingly being established in Europe for enhancing arthropod conservation and the provision of ecosystem services, including biotic pollination and natural pest control. Here we use floral traits to identify different plant functional effect groups. Floral resources were provided in four experimental levels characterised by a cumulatively increasing flower trait diversity and vegetation stand complexity. The first level consisted of a bare control strip, whilst in each subsequent level three wildflower species with different functional traits were added (Level 0: control; Level 1: three Apiaceae species; Level 2: three Apiaceae and three Fabaceae species; Level 3: three Apiaceae, three Fabaceae species, and Centaurea jacea (Asteraceae), Fagopyrum esculentum (Polygonaceae), Sinapis alba (Brassicaceae)). Plots with sown wildflower strip mixtures were located adjacent to experimental plots of organically-managed tomato crop, which is attacked by multiple pests and partially relies on bees for fruit production, and hence dependent on the provision of pollination and pest control services. Results obtained here show that the inclusion of functionally diverse wildflower species was associated with an augmented availability of floral resources across time, and this increased the abundance of bees and anthocorids throughout the crop season. Several natural enemy groups, such as parasitoids, coccinelids and ground-dwelling predators, were not significantly enhanced by the inclusion of additional flower traits within the strips but the presence of flower resources was important to enhance their conservation in an arable cropping system.

Utilisation of plant functional diversity in wildflower strips for the delivery of multiple agroecosystem services

Increased plant diversity in cropping systems can play an important role in agriculture by enhancing arthropod‐mediated ecosystem services, including biological control and pollination. However, there is limited research investigating the concurrent influence of plant functional diversity within cultivated systems on different arthropod functional groups, the provision of multiple ecosystem services, and crop yield. During a field experiment, repeated over 2 years, we measured the effect of increasing plant functional diversity on community structure of arthropod visitors, the abundance of multiple pests and induced crop damage, and fruit production in two varieties of tomato. Plant resources (floral and extra‐floral nectar and pollen) were included within experimental plots in four levels, with each level increasing the plant functional group richness, based on floral morphology and availability of resources, in a replacement series. The presence of sown flower mixtures in experimental plots was associated with increased abundance and diversity of natural enemy functional groups and an enhanced abundance of bees (Hymenoptera: Apiformes). However, we only detected relatively small variability in arthropod visitors among types of mixtures, and increased abundance of natural enemies did not translate into stronger pest suppression or reduced crop damage. Lepidoptera pest damage was significantly higher in plots adjacent to wildflower strips, an ecosystem disservice, but a significantly higher crop productivity was recorded from these plots. Our results provide evidence that inclusion of non‐crop plant resources in agroecosystems can improve the conservation of beneficial arthropods and may lead to increased crop productivity.

Arbuscular mycorrhizal fungi shift competitive relationships among crop and weed species

AimsArbuscular mycorrhizal (AM) symbioses affect plant competitive relationships within and among species and may be involved in the interactions among agricultural weed species and crops, depending on their mycorrhizal status. In this work, the impact of native AM fungi (AMF) on maize-weed(s) and weed–weed competitive relationships was assessed, using Solanum nigrum and Chenopodium album as model host and non-host weeds, respectively.MethodsGrowth performance, nutrient use and competitive ability of crop and weed species were assessed in the pure stand and in different model plant communities of host and non-host species.ResultsResults showed that maize performance decrease was more severe when grown with C. album than with S. nigrum. Differential responses to AMF occurred in the two weed species tested: mycorrhizal S. nigrum showed reduced biomass and N uptake when grown in competition with C. album. The negative performances observed when mycorrhizal S. nigrum grew in competition with C. album corresponded to C. album larger biomass production and N uptake.ConclusionsResults showed that AMF are able to alter the competitive relationships between co-occurring plant species differing in their mycorrhizal status (host/non-host), thus representing key soil organisms to be taken into account in sustainable weed management strategies.

Landscape complexity and field margin vegetation diversity enhance natural enemies and reduce herbivory by Lepidoptera pests on tomato crop

Agricultural intensification may lead to higher pest pressure through the loss of natural plant assemblages, and associated reduction in natural enemy diversity, while providing increased crop area. We investigate the influence of field margin vegetation and landscape complexity on natural enemy diversity and crop damage caused by two Lepidoptera tomato pests (Tuta absoluta and Noctuidae). At the local scale, fields were bordered with herbaceous field margins of varying vegetation diversity. At the landscape scale, these fields were set in landscapes with increasing landscape complexity. Margin vegetation diversity was higher in landscapes with lower arable land cover, and was associated with increased floral resources and enemy diversity, with the latter being negatively related to T. absoluta-caused fruit injury. Total crop damage increased with arable land cover. These results imply that the suitability of farming practices for the conservation of natural enemies and pest control services is influenced by the landscape context.

The Territory Agronomy Approach in research, education and training

Landscape and territory agronomy analyses the two-way relationship between farming practices and land patterns. It takes into account both agro-environmental and socio-economic processes. A conceptual framework is presented to facilitate understanding of the complex interactions between the disciplines that contribute to this new field of research. We discuss the organisational issues that arise at various spatial and temporal scales during the development of territory-based case studies and research projects. The territory agronomy approach is a participatory action science. Building on our experiences, we propose a conceptual research-education-action platform for land management and territorial development. It demonstrates that the Territory Agronomy Approach is an iterative process where researchers, teachers, trainers and stakeholders develop new questions and methods through participation. These characteristics make the territory agronomy approach adapted to promote the territorial dimension in research, education and training activities on farming systems.