Self-produce Part of Your Cover Crop Seeds
The use of farm-produced seeds is authorized for 34 species, including several that can be used in intermediate crops. The list of concerned species, defined by a European regulation in 1994, was expanded by a decree in 2014.
Among the surveyed farmers, eleven use cover crop seed multiplication to limit the cost of their generally complex mixtures. Most farmers multiply only one or two species and purchase the other species in the mixture.
Potential gain
The economic interest is very variable from one species to another depending on its seed yield, but especially its seeding rate:| Species | Gain per kg (€) | Seeding density (kg/ha) | Gain per ha (€) |
|---|---|---|---|
| Spring oat | 0.38 | 80 | 30.16 |
| Wild oat | 1.23 | 35 | 42.88 |
| Winter field bean | 0.31 | 200 | 61.19 |
| Spring field bean | 0.37 | 200 | 74.03 |
| Oilseed flax | 1.34 | 25 | 33.59 |
| Winter pea | 0.52 | 125 | 64.56 |
| Spring pea | 0.35 | 125 | 43.44 |
| Forage pea | 1.14 | 70 | 79.95 |
| Spring vetch | 0.81 | 35 | 28.24 |
1. First, all operational costs applied to the crop are summed.
2. The gross margin of a "substitute" crop (which would be planted at the same stage of the rotation) is added to this production cost (to account for the land occupation by the crops used for seed multiplication and thus the gross margin not realized with another crop). The "substitute" crops are wheat when it is a grass and rapeseed when it is an dicotyledon species being multiplied. The subtracted gross margins take into account the farmer's sector and practices (cost level and yield).
3. When the multiplied species is eligible for the protein crop premium, the amount of this premium is subtracted from the costs.
4. The resulting sum corresponds to the production cost of seeds per hectare. This amount is then divided by the yield in kilograms that the farmer obtains for the multiplied species. The result corresponds to the seed cost per kilogram.
Most farmers who multiply their cover crop seeds use sorting. For a limited cost (around 2 to 3 cents per kilogram of sorted seeds), they obtain clean seed. The operation is sometimes necessary to remove plant debris that could clog the seeder or weed seeds potentially present in the seed. Some surveyed farmers sometimes skip this step when the combine harvester allows satisfactory separation.
Field choice
Regarding the fields chosen for seed multiplication, the farmers interviewed mentioned various decision rules. For some, choosing drying fields like cranette was interesting to have rapid seed maturity. For others, planting new crops allows the introduction of crop heads (legumes) in fields where it is difficult for them to plant their usual rotation heads (small fields, enclosed fields). Finally, for multipliers without particular constraints, the multiplication crops are planted next to crops with similar technical itineraries to simplify management.
Innovative practice: crop association
Among the surveyed farmers, three of them used crop associations to produce part of the seed of their cover crops.
Rapeseed - field bean association
In the Aube, a farmer associates his rapeseed with winter field beans. The development within the rapeseed is satisfactory, and if the winter frost is not too severe, the field beans survive in the rapeseed. He has harvested winter field beans 4 years out of 6 since he started this association with a field bean yield around 5 qx/ha. He has not observed any negative impact on rapeseed yield. The technique requires good adjustment of the combine harvester to avoid losing either rapeseed or field beans. The farmer is equipped with a sorter to separate the two harvests.
In the Aube, a farmer associates his rapeseed with winter field beans. The development within the rapeseed is satisfactory, and if the frost is not too severe, the field beans survive in the rapeseed. He has harvested winter field beans 4 years out of 6 since he started this association with a field bean yield around 5 qx/ha. He has not observed any negative impact on rapeseed yield. The technique requires good adjustment of the combine harvester to avoid losing either rapeseed or field bean. The farmer is equipped with a sorter to separate the two harvests.
Field bean - spring vetch association
After an unsuccessful attempt to multiply vetches (flattened by a storm), a farmer from the Somme decided to associate them with spring field beans. The latter serve as support and their seeds are valued in the cover crops. These two crops have staggered maturity dates. To have coordinated maturity of both species, he sows the field beans first then the vetches 3 to 4 weeks later. The technical itinerary is the same for both species. He harvests both together then sorts the seeds. Given the late maturity of these species (August), the farmer has built up a stock and sows the self-produced seeds from the previous year in July.
Camelina - spring vetch association
Apart from potentially considerable sitona damage, the technical itinerary to produce vetches is very simple. The main difficulty lies in harvesting a crop that is often flattened. To remedy this, a farmer surveyed in the Aisne associates his vetches with camelina to keep them upright until harvest. He also builds up a stock to be able to sow the vetches harvested the previous year. He obtains each year a yield of about 25 qx/ha of vetches.
Source
Agro-Transfert Resources and Territories (2022). Innovative practice sheet: Producing part of your own cover crop seeds. Project "Multifunctionality of cover crops".
Available at: https://cultivons-les-couverts.agro-transfert-rt.org/autoprod/index.html
