Late mowing

Technical articles - Biodiversity, Soil erosion

Livestock Livestock Agroecology Meadows

© M.Ancely

Late mowing consists of mowing a plot after the peak flowering of meadow species. This delay also helps to avoid overlapping the reproduction periods of certain species with the mowing period of meadows.

Principle

This technique is truly beneficial for preserving floral diversity, which attracts a diversity of insects, but also provides a shelter for wildlife.

Positive impact on flora

Most species can complete their reproductive cycle and produce seeds. Floral diversity provides nectar and pollen for many invertebrates (beneficial insects, pollinators…), which in turn attract their predators (bats, amphibians, reptiles, birds…).

Positive impact on fauna

Leaving tall grasses longer allows ground-nesting birds, such as larks or partridges, to successfully raise their broods, and mammals like hares or juvenile roe deer to grow safely. These areas thus serve as refuge zones, but also as ecological corridors for wildlife. These zones are part of what is called the green infrastructure of agricultural landscapes, complementary to the blue infrastructure and hedgerows.

File:Reproduction calendar.png

Reproduction calendar of some species present in the field, AGROBIO 35

Implementation

Equipment

During mowing, the higher the cutting height, the less impact on plant and animal species living near the ground; therefore, the cutting bar should be raised as much as possible. Sickle bar mowers help reduce the number of casualties, while rotary mowers tend to "suck in" wild animals.

Mowing periods

Several documents and institutes recommend the date of July 15, but this may vary depending on the regions and intentions.

Fertilization

Fertilization tends to decrease floral diversity by favoring a few competitive species. It is better to fertilize meadows little or not at all.

Benefits

Working time

Late mowing does not increase working time (15 min to 1h/ha depending on tractor speed). Annual working time may decrease, as this technique involves only one mowing per plot.

Floral biodiversity

• The abundance of insects increases pest bioregulation services and pollination.
• Diverse root systems help regulate Erosion with better water retention.
• It also promotes landscape heterogeneity and enhances the farmer’s image to the public.

Seed savings

Since most flowers complete their reproductive cycle, the meadow reseeds itself. Seeds can also be found in animal droppings, which will disperse these species further.

Limits

Decrease in productivity

This type of meadow can produce 1 to 5 t DM/ha, which can sometimes be lower than other mowing meadows. It can be applied only on some plots.

Decrease in forage value

The nutritional value of late-mown meadows is generally always lower, in terms of digestible protein and minerals, than that of earlier-mown meadows.

Going further with "friendly" mowing

Friendly mowing encompasses a set of practices that can be implemented to reduce the mechanical impact of mowing and harvesting on small fauna:

• Perform strip mowing or centrifugal mowing (from the inside out) to avoid trapping fauna (and insects) in the center of the plot.
• Maintain a speed under 10 km/h.
• Cutting height between 7-8 cm.
• No night work.
• Use of scaring bars.
• Leave unmown refuge zones on the plot.
• Count the number of individuals killed per plot.

Cette technique s'applique aux cultures suivantes

• Permanent meadows
• Temporary meadows

La technique permet de favoriser la présence des auxiliaires et bioagresseurs suivants

• Pollinators
• Crop auxiliaries

Cette technique utilise le matériel suivants

• Sickle bar mowers
• Scaring bar