Some of you may still be wondering why, in many departments, we no longer mow embankments, ditches or meadows in the spring. We sometimes wait for the summer or even the fall. This is called late mowing. It benefits nature as a whole, it gives flowers time to set seed, and insects their job as pollinators.
Again this summer, new departments or municipalities got into it. The municipal council of Gérardmer has just matched the premium per hectare of €16,000 to farmers with recommendations in favor of this late mowing. In Luxembourg, it is downright the government that recommends that they do the first mowing of the year as late as possible. Even golf courses are getting into it when we imagine that we need a smooth green. There is also an environmental golf charter: among the recent converts, that of Haut-Poitou in Beaumont-Saint-Cyr where the presence of a dandelion is no longer perceived as a disaster, but as a joyful challenge. They will even begin an inventory of the fauna and flora.
We can quantify the gain in biodiversity: 30% more pollinators, in three years, along the national roads on which the government launched an experiment in 2015. Since 2018, this practice has been generalized over the 12,000 km of the unlicensed national network. Unless there is a question of safety of course, in a bend where tall grass would hinder visibility. Another example: in Poitiers, in late mowing areas, the entomologist appointed by the municipality listed 63 different species of insects, while in mowed areas, only 11.
As far as agriculture is concerned, it’s really on a case-by-case basis. In the plains of the Great West, dairy farmers continue to mow early and several times a year because they need hay to feed the animals. Under pressure in particular from the milk industry. But researchers at the Inational research institute for agriculture, food and the environment (Inrae) are formal about the benefits in the plains as well as in the mountains. “It allows you to naturally get rid of certain diseases, fungi or insects”, explains Catherine Picon-Cochard, who heads the Prairial Ecosystem Unit. On the side, other insects or wild plants can come and settle in to clean up the neighboring field.
Does this increase the fire risk? Again, there is no simple answer. When it is very dry, this can in fact facilitate the outbreak of fire. After the terrible fires in Gironde in July, the Federation of Private Foresters also asked the Minister of Agriculture to review all these practices. But beware, says INRAE, late mowing precisely helps maintain humidity and freshness on the ground, in the shade.
Moreover, the plants that are mowed less do not exhaust themselves in constantly redoing leaves. They therefore grow back more vigorously following fires. Last advantage: for greenhouse gases this time and therefore the climate. If we are to believe the association of professional gardeners: the late mowing has significantly increased methanisation, the quantity of plant waste generating many more liters of green fuel.