Herb-rich, perennial ﬁeld margins along arable ﬁelds, meadows, farm tracks, ditches, and hedgerows are important structural elements in agricultural landscapes, providing feeding, breeding, and hibernation habitats for many animals (birds, butterﬂies, wild bees, hoverflies, grasshoppers, ground beetles, spiders) and, in general, characterising the landscape. In the intensively farmed regions of northern and eastern Germany, existing ﬁeld margins are mostly species-poor and grass-dominated, thus not able to fulﬁl their ecological and aesthetic functions.
Unfortunately, in restoration and establishment of fringes and field margins, mostly commercial standard seed mixtures are used, containing horticultural and agricultural varieties, ﬂowering plants of non-native origin (e. g. Petroselinum crispum, Dianthus barbatus, Alcea rosea), and even invasive species such as Bunias orientalis or Lupinus polyphyllus.
Diversiﬁcation of still-existing ﬁeld margins and the re-establishment of already vanished ﬁeld margins establish biotope networks in the landscape, thus contributing to the conservation and enhancement of biological diversity in the concerned region. The use of herb-rich seed mixtures containing 30-40 native species from regional propagation is a decisive precondition for the long-term success of these measures.
Deﬁcient establishment of species-rich ﬁeld margins, in regards to the use of seed mixtures of local provenance were analysed and best practice methods for the establishment of site-speciﬁc perennial ﬁeld margins on nutrient-rich sites were tested. The implemented seed mixtures should satisfy aesthetic demands and the developing vegetation should require low management efforts. In addition, the seed mixtures should be suitable not only for restoration and re-vegetation of different ﬁeld margins, but also for other green spaces. In Saxony-Anhalt, the results of this project were implemented into the agri-environmental scheme for the establishment of flower strips in the CAP funding period 2014-2020.
Pilot trial – Establishment of a field margin along arable land
Adjacent to the experimental ﬁeld Ochsendorf on the Campus Strenzfeld, a block trial with six variants and ﬁve repetitions was established begin of October 2010. For the sowing variants, the species-poor, grass-dominanted ﬁeld margin was destroyed by grubbing (1x, 3x). On the 7th of October 2010, 49 regional wild plant species (e. g. Anthemis tinctoria, Betonica ofﬁcinalis, Campanula patula, Clinopodium vulgare, Dianthus carthusianorum, Hypericum perforatum, Knautia arvensis, Leucanthemum ircutianum, Malva sylvestris, Salvia pratensis, Securigera varia) were sown on the unvegetated variants with 2 g/m² (c. 2000 seeds/m²).
On two variants, the existing vegetation was not disturbed and no seeding took place; one of these variants was mown in the ﬁrst year once (begin of October) and the other thrice (begin of June, mid of July, begin of October). During the establishment phase, the grubbed and sown sites were mown twice (begin of June, end of August 2011).
Since 2012, half the sites are mown once in early summer (June), the other half once in late summer (begin of September) with removal of biomass.
Several large-scale demonstration trials were established in the administrative districts Salzlandkreis, Anhalt-Bitterfeld (both Saxony-Anhalt) and Osnabrück (Lower Saxony) in spring and autumn 2011 with the cooperation of resident farmers. The demonstration trials are comprising on the one hand the creation of new species-rich ﬁeld margins and on the other hand the diversiﬁcation of still existing, species-poor remnants. For establishing these plant communities, site-speciﬁc, regionally produced seed mixtures with species from local origin were composed. On all sites, vegetation development will be documented on permanent plots via relevés with percentage coverage of species and layers.
In addition, ﬁve still existing species-rich ﬁeld margins on dry and mesic sites per geographic region were selected for vegetation analysis. These ﬁeld margins are used as reference sites for comparison with the demonstration trials.
On the Internet platform www.offenlandinfo.de useful information about restoration, establishment and management of species-rich ﬁeld margins are shown for interested users (e. g. farmers, planners, public authorities). Furthermore, until the end of the project, suitable strategies for marketing of regionally produced seeds of local origin will be developed to facilitate and promote the use of these seed mixtures in ecological restoration.
Practical guidelines for establishing fringe communities and field margins
Based on our project results, we made recommendations for planning, implementation, and management of fringe communities and field margins. A comprehensive description (in German language) can be found in Kirmer et al. (2014); a more general guideline to establish flower-rich structures in urban and rural areas can be found in Kirmer et al. (2019).
1. Soil preparation: Establishment success of sown species in grass margins generally increases with greater disturbance. Soil preparation may be accomplished by tilling, grubbing or plowing followed by harrowing to produce a fine seed bed.
2. Sowing time: Late summer sowing (late August to mid-September), shortly before the rainy season starts is most successful. Spring sowing (early March to mid-April) is possible, but risky in years with spring drought. Seed of wild plants require at least 2-3 weeks of moist weather conditions for germination.
3. Sowing method: Drill seeding followed by rolling is recommended. Seeds should be dropped on the soil surface and not covered as most wild species require light for germination.
4. Sowing density: A maximum of 2 g/m² sowing density is recommended. Filler material (e.g. bruised grain) at rates of 10-20 g/m² may be required to improve seed distribution.
5. First year management: Undesirable species (e.g. Atriplex spp., Chenopodium spp.) are effectively reduced with 2-3 cuts to c. 10-15 cm height. Cuttings should be removed, except during drought periods and on sites with low biomass production. Selective mowing is required if problematic species (e.g. Arctium spp., Carduus acanthoides, Cirsium arvense) or invasive neophytes emerge. Timely management during the bud stage and prior to flowering is mandatory.
6. Normal management: On nutrient-rich sites, mowing with removal of biomass in early summer is more successful than late mowing (September). Because stepwise mowing is essential to guarantee continuous flowering for insects, up to half of the site should be mown between mid-May and mid-June and the remainder 8-10 weeks later (between end-July and mid-August). On low-productive, nutrient-poor sites, only half of the sites can be mown (e.g. in early summer), but the mowing schedule must be alternated yearly to avoid grass dominance in uncut parts.
Management Hochschule Anhalt: Prof. Dr. Sabine Tischew, Prof. Dr. Dieter Orzessek
Researchers: Dr. Anita Kirmer, Dipl.-Ing. (FH) Matthias Necker
Funded by: Bundesministerium für Bildung und Forschung (FHprofUnt Programm)
Project partners: Hochschule Osnabrück / Osnabrück University of Applied Sciences; Prof. Dr. Kathrin Kiehl (lead partner)
Cooperation partners: Landwirtschaftsbetrieb Matthias Saudhof; Agrico Lindauer Naturprodukte AG, Hans-Joachim Wuttig;
Landschaftspflegeverein Saaletal e.V.; Rieger-Hofmann GmbH; Matthias Stolle Wildpflanzenvermehrung und –handel