Growing Low Nitrogen-Demanding Species
Some crops are characterized by low nitrogen fertilization needs, due to reduced unit needs (barley, oats, triticale, rye...) and/or more limited yield potentials (sunflower, flax…), or because they are nitrogen self-sufficient (legumes).
Authors:
| Marjorie Troussard | CA 85 | marjorie.troussard(at)vendee.chambagri.fr | La Roche sur Yon (85) |
|---|---|---|---|
| Alexandra Cherifi | Agricultural and viticultural farm Auxerre - La Brosse | alexandra.cherfifi(at)educagri.fr | Auxerre (89) |
| François Dumoulin | CA 60 | francois.dumoulin(at)agri60.fr | Fresnoy le Luat (60) |
| Rémy Ballot | INRA | remy.ballot(at)grignon.inra.fr | Grignon (78) |
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Presentation
Technique characterization
Example of implementation:
In rotations dominated by small grain cereals, maximize the share of cereals with low unit needs (barley, oats, triticale, rye rather than wheat); In rotations dominated by spring crops, reduce the share of corn in favor of sunflower or soybean...
Details on the technique:
Some crops with low or no nitrogen requirements (-sunflower, protein crops…) often generate a less attractive margin than more demanding crops (wheat, corn…). But it is important to consider the profitability at the cropping system scale, including beneficial effects for other crops in the rotation (nitrogen restitution, weed pressure...).
Low nitrogen requirement crops: Winter oats, Spring oats, Winter fiber flax, Spring fiber flax, Winter seed flax, Spring seed flax, Winter barley, Spring barley, Winter rye, Spring rye, Sunflower, Winter triticale, Spring triticale, Buckwheat.
Legumes: Fenugreek, Winter faba bean, Spring faba bean, Vetch, Bean, Green bean, Lentil, Winter sweet white lupin, Spring white lupin, Spring blue lupin, Alfalfa, Sweet clover white or yellow, Pea, Chickpea, Winter pea, Spring pea, Sainfoin, Soybean, White clover, Alexandrian clover, Micheli clover, Persian clover, Crimson clover, Purple clover, Common vetch.
Application of the technique to...
Implementation period On established crop
Spatial scale of implementation Plot
All crops: Not generalizable
All soil types: Easily generalizable. Choose crops according to their adaptation to soil type: e.g. faba bean in soil with good water reserve, sunflower in drying soil…
All climatic contexts: Easily generalizable. Choose crops according to their adaptation to the climatic context.
Regulations
POSITIVE influence : MAE diversification of crop rotations
Effects on cropping system sustainability
"Environmental" criteria
Effect on air quality: GHG emissions: DECREASE.
Introducing low nitrogen requirement plants into the rotation helps limit the release of greenhouse gases linked to the manufacture of mineral fertilizers. It also helps limit nitrous oxide emissions and ammonia volatilization proportionally to the reduction in nitrogen fertilization dose allowed.
Effect on water quality: Variable
Introducing low nitrogen requirement crops into the rotation helps limit nitrate transfer risks by leaching proportionally to the reduction in fertilization dose allowed. Be careful, in the case of legumes, the post-harvest residue can cause higher loss risks. This risk can be reduced by planting after legumes a crop rapidly utilizing available nitrogen (e.g. rapeseed).
Effect on fossil resource consumption: Decreasing.
Introducing low nitrogen requirement plants into the rotation helps limit energy consumption linked to the manufacture of mineral fertilizers, which often constitutes the largest energy expense in large-scale cropping systems.
"Agronomic" criteria
Productivity: Variable
Replacing high unit need crops with lower unit need crops has no effect on system productivity (example: rye or triticale replacing wheat). However, replacing high potential crops with lower potential crops logically leads to a decrease in productivity (example: sunflower replacing corn).
Soil fertility: No effect (neutral)
Few references are available, but crop diversification in the rotation, especially by introducing legumes, tends to improve fertility.
Functional Biodiversity: Increasing
Introducing low nitrogen requirement species into the rotation helps limit mineral fertilizer inputs, thus limiting their negative impact on soil life and promoting soil biological activity.
"Economic" criteria
Operating costs: Decreasing
Introducing low nitrogen requirement species into the rotation helps limit nitrogen fertilizer inputs, which constitute a significant expense, thus reducing fertilization costs.
Mechanization costs: Variable
Introducing new crops may require specific investments (adaptation of harvesting equipment, contracting, storage …)
Margin: Variable
The impact of introducing low nitrogen requirement species into the rotation varies depending on the species introduced, its yield potential, and its selling price…
"Social" criteria
Working time: Variable
Introducing low nitrogen requirement species can reduce the number of passes needed for fertilizer spreading. It also helps spread the workload by diversifying the cropping system.
Observation time: Variable
Introducing low nitrogen requirement species reduces the observation time needed for nitrogen fertilization management, but crop system diversification generally requires more observations.
For more information
- Diversify species for better agronomic management in organic farming - DevAB sheet no. 4, Technical brochure, 2009, link to the brochure.
