Maintenance of grassy areas
A herbaceous area in good ecological condition is an area composed of several families of flowering plants that are not weeds for crops. To maintain an optimal composition, any disturbance (soil tillage drift, fertilization, or phytosanitary treatment) that could cause the germination and development of weed plants must be avoided. In this case, it is possible not to maintain the grass areas which are essential for the small wildlife of the plain. However, after several years, a grass strip or a fallow may become overrun and turn into a reservoir of weeds (e.g., field thistle). Mechanical maintenance is a solution to limit overgrowth.
Objectives and Expected Benefits
Herbaceous areas are a highly prized nesting and rearing site for young by the plain's birdlife[1]. In a qualitative approach, it is possible to let farmers choose the maintenance method they prefer, before seed set. The ultimate objective is to have heterogeneous management of herbaceous areas at the landscape scale[2][3].
Mechanical maintenance can cause a decrease ranging from 30 to 50% in populations of arthropods, 50% of the spider population, 30% of the rove beetle population, and 36% of the population of ground beetles[4].
Methodology
Selective Maintenance of Problem Areas
The objective is to maintain a refuge cover for wildlife at least during the breeding period. If the cover is maintained only in problem weed areas and between 30 cm and 40 cm, then the objective is achieved. The advantage is also to maintain a fundamental herbaceous cover for the protection of beneficial insects[5]. This results in a non-uniform cover with some areas mowed and others intact.
Expert Statement
- "Selection of problematic areas: Best compromise between beneficial insects and agriculture in case of localized infestation of problematic weeds.
- Maintenance height 30 to 40 cm: Beware, close mowing in spring spares only 10% of insects".
Jean Pierre Sarthou, Agro Toulouse INP, INRAE AGIR
The least impactful and most economical maintenance method for beneficial insects is mowing.
Winter Maintenance
If the composition allows, it is possible to maintain herbaceous areas only in winter without risking overgrowth in the plots. This practice reduces maintenance costs and lowers the risk of overgrowth in the adjacent cultivated plot[6].
Expert Statement
"A winter maintenance (around January) and at height (30 to 40 cm) saves 80% of insects. Beware, autumn (which is a small spring) is a breeding period for some beneficial insects." Jean Pierre Sarthou, Agro Toulouse INP, INRAE AGIR
Regulatory Limits
Currently, regulations impose a no-maintenance period for field margins or fallows generally spread over May/June. This period corresponds to the nesting period of insects and ground-nesting birds but also to the seed set period of weeds such as ryegrass, blackgrass, field thistle... Due to this regulation, there is an increase in mowing in plots the day before and after the forbidden period. In this situation, herbaceous areas lose all their value as shelter for wildlife and as a reservoir for beneficial insects.
How to Implement This Practice on My Farm?
As with field margins, it may be relevant to conduct a survey or floristic inventory on herbaceous areas: fallow or grass strip. Depending on the weed flora present, its location, and the type of cover, the appropriate maintenance method can be chosen.
In case of weed problems, if the overgrowth issue on the crop edge persists, a diagnosis and more global measures will be necessary. (See sheet Promoting biodiversity by optimizing field margins).
| Type | Problematic weed (blackgrass, ryegrass…) | Volatile weed (thistles…) | Equipment |
|---|---|---|---|
| Field margins (0.5 to 1.5 m wide) | Localized regular topping | Localized topping at flowering | Mower |
| Grass strip type GAEC (Good Agricultural and Environmental Conditions) (min 5 m wide) | Localized regular topping
Maintenance of the first meter of crop edge at 30 or 40 cm above ground!! Beware of nests!! | ||
| Fallow |
Advice
In the case of invasive species (Japanese knotweed, giant hogweed, common ragweed, ...), chemical control remains the most effective, fastest, and most appropriate technique to eliminate them while respecting current regulations. Indeed, rapid elimination of these species is necessary to limit damage to the agroecosystem.
For more information on invasive exotic species and management methods, click here.
Maintenance of herbaceous areas can expose a pheasant or partridge nest. It will then be abandoned by the mother as it becomes visible to predators. It is then possible to contact the technical service of your departmental hunters' federation who can take care of the eggs.
To Go Further
The most interesting maintenance method to preserve optimal ecological diversity for beneficial insects is mowing with export[7].
Sources
- ↑ 1 Bro E.; 2016. The Grey Partridge. Biology, Ecology, Management and Conservation. Biotope, Mèze, 304p
- ↑ Kruess A.; 2002. Grazing Intensity and the Diversity of Grasshoppers, Butterflies, and Trap‐Nesting Bees and Wasps, Society for Conservation Biology, Volume 16, Issue 6, p1570-1580.
- ↑ Cizek O. et al.; 2012. Diversification of mowing regime increases arthropods diversity in species-poor cultural hay meadows, Journal of Insect Conservation, no.16, p215-226.
- ↑ Thorbek P. et al 2004. Reduced numbers of generalist arthropod predators after crop management British Ecological Society, Journal of Applied Ecology, 41, p526–538
- ↑ Le Bris C.; 2011. Management of field margins and biodiversity in cereal plains, Faune sauvage no.291, p64-70.
- ↑ Le Bris C. et al.; 2014. How to reconcile agronomy and biodiversity of field margins in cereal plains? - Summary of Agrifaune Loiret and Eure-et-Loir experiments. Faune Sauvage. no.305, p38-44.
- ↑ Noordijk J. et al (2010), Effects of vegetation management by mowing on ground-dwelling arthropods, Ecological Engineering, Volume 36, Issue 5, Science Direct, p740-750
Annexes
- Redirect Modèle:Pages liées
