PARTRIDGE project partners in Germany test a new wild flower mix for autumn sowing
Some farmers at our PARTRIDGE project areas in Diemarden and Nesselröden have difficulties working on fields in the spring, when clay soils can be very heavy and wet. Therefore, they prefer autumn sowing for new flower blocks. We have developed the “Göttingen Mix” for spring sowing, as it contains many annual, frost sensitive species, as sun flower, Phacelia, buckwheat, linseed etc. To allow for autumn sowing a revised mix is needed that will include hardy plant species.
Recently, there has been some criticism of flower block seed mixes by entomologists in Germany and other parts of Europe, as they are mainly composed of introduced crop plants, instead of native species. Insects such as wild bees have very specific requirements when it comes to their food plants, so entomologists think that a native mix would provide better food resources for insects. The botanists of the Authority for Nature Conservation of Lower Saxony for example, avoided including native species in flower strip mixes. They were concerned about potential negative impacts on local wild native plant populations due to the use of seeds that were not sourced locally. This could lead to genetic contamination, in particular with timing of germination as plants adapted from horticultural propagation have been selected to germinate at the same time, compared to the more heterogeneous germination seen in the wild.
Obviously, the views of zoologists and botanists can be quite different.
Composition of the new mix
Within the PARTRIDGE project we are free to use our own seed mixes without considering the directives of agri-environment schemes (AES). We took the opportunity to create a new seed mix for autumn sowing composed mostly of native species. Additionally, we chose a seed supplier who offers seeds of local genetic origin for each of the regions in Germany.
The species selected for our German autumn-sown wild flower PARTRIDGE mix met the following criteria:
- Fit the image of flowering, ruderal vegetation
- Fit the type of cultivation (50% of the area is power harrowed) in spring in order to renew the vegetation and to produce an open and heterogeneous structure)
- Should be able to compete with weeds
- Attractive to pollinating insects
- Competitive price: some seeds of native species are very labor-intensive to produce/harvest and therefore very expensive. We avoided the very expensive species to make the mix affordable.
Our calculations for the mix (Table 1) considered two things:
- The weight of a single seed. For instance, corn flower (Centaurea cyanus), that has rather heavy seeds, made up a higher percentage of the weight of the mix).
- Competitiveness. Highly competitive plants such as sweet clover (Melilotus officinalis and Melilotus albus) were included at a lower proportion in order to avoid one species becoming dominate.
We had already asked farmers to agree to the inclusion of two “weed” species (poppy - Papaver rhoeas - and cornflower) in the mix.
Table 1: Composition of the new seed mixture for autumn sowing: Many species are very attractive to wild bee species or hoverflies; some to butterflies as well. *Annual = plants that live for only one growing season), biennial = plants which require two years to complete their life cycle, perennial = plants that persist for many growing seasons.
|
Weight proportion |
Species |
*Annual, perennial or biennial |
|
15.0 |
Cornflower (Centaurea cyanus) |
annual |
|
8.0 |
Viper’s bugloss (Echium vulgare) |
biennial |
|
5.0 |
Yarrow (Achillea millefolium) |
perennial |
|
5.0 |
Cota tinctoria (Anthemis tinctoria) |
perennial |
|
5.0 |
Chicory (Cichorium intybus) |
perennial |
|
5.0 |
Wild carrot (Daucus carota) |
biennial |
|
5.0 |
Teasel (Dispsacus fullonum) |
biennial |
|
5.0 |
Oxeye daisy (Leucanthemum ircutianum) |
perennial |
|
5.0 |
Bird's-foot-trefoil (Lotus corniculatus) |
perennial |
|
5.0 |
Common poppy (Papaver rhoeas) |
annual |
|
5.0 |
Dyers rocket (Reseda luteola) |
biennial |
|
5.0 |
Wild rye (Secale multicaule) |
perennial |
|
5.0 |
Red campion (Silene dioica) |
perennial |
|
5.0 |
White campion (Silene latifolia) |
perennial |
|
3.0 |
Wild cabbage (Brassica oleracea) |
biennial |
|
2.0 |
Brown knapweed (Centaurea jacea) |
perennial |
|
2.0 |
Woad (Isatis tinctoria) |
biennial |
|
2.0 |
Common mallow (Malva sylvestris) |
perennial |
|
2.0 |
Parnsip (Pastincaca sativa) |
biennial |
|
2.0 |
Red clover (Trifolium pratense) |
perennial |
|
2.0 |
Dense-flowered mullein (Verbascum densiflorum) |
biennial |
|
1.0 |
Yellow sweet clover (Melilotus officinalis) |
biennial |
|
0.5 |
White sweet clover (Melilotus albus) |
biennial |
|
0.5 |
Tansy (Tanacetum vulgare) |
perennial |
|
100.0 |
|
|
Fig. 1: Composition of the new mix; the larger seeds are Isatis (woad) and Pastinaca (wild parsnip).
We decided to choose a very low sowing density of 3 kg/hectare for the following reasons:
- The species in the seed mixture need a very different amount of time to establish. Some start with large seedlings and grow quicker, others start from tiny seeds. We wanted to avoid strong competition following planting in order to give all species a chance of germination and to allow any native arable flora in the soil to germinate. The aim is to achieve a species-rich vegetation with good structure.
- The “Göttingen Mix” was sown successfully with 7 kg/ha at our German PARTRIDGE demo sites. The new mix contains much smaller sized seeds, with the result that it contains more seeds within the same weight of mix, so should be sown less dense than the “Göttingen Mix”.
- Most plots taken out of production for our new wild flower PARTRIDGE plots have been farmed conventionally using herbicides to grow crops. Therefore, we do not expect a pernicious weed problem in the first spring following the sowing of our new mix.
- Price, using less of the seed mixture will result in a more economically viable approach and mean that it is more likely to be used for future measures and projects.
Farmers might have difficulties spreading 3 kg over one hectare. We therefore diluted the mix by the same amount of linseed (50% mix, 50% linseed). That means 6 kg/hectare of the linseed diluted mix can be sown. This compares to the conventional sowing of oilseed rape at 2-6 kg/hectare.
The price for the seed mix to sow one hectare is 192 € (linseed included).
Fig 2. Lisa Dumpe diluting the German autumn-sown PARTRIDGE mix with linseed, in preparation for sowing.
Written by Lisa Dumpe and Eckhard Gottschalk, edited by Julie Ewald, Francis Buner and Holly Kembrey