Potential of crop mixtures to reduce pesticide use in France. A data analysis
Résumé
Over the last 50 years, agricultural intensification has led to simplified agricultural systems
highly dependent on fertilisers and pesticides, causing biodiversity loss, changes in the balance
of nutrients, water and soil contamination. The total amount of pesticides applied each year
in France makes it the main consumer of plant protection products in Europe, and arable crops
are currently the most pesticide-consuming production systems. Reducing pesticide use in
arable crops is thus a major challenge. There is now evidence that crop diversification in time,
with more diversified rotations, and in space, through crop mixtures, can help restore
ecosystem services and represent a potential key lever to reduce pesticide use (Lechenet et
al., 2016). However, research has often analysed the effects of crop mixtures on pesticide use
over small areas (e.g., single plots or fields), whereas these effects need to be evaluated over
larger and more realistic spatial extents to fully assess their potential to reduce pesticide use.
By focusing on species mixtures, we aim to (i) quantify the potential of crop mixtures for
pesticide use reduction in France and (ii) identify the drivers of mixture use leading to its
temporal and spatial dynamics observed at a national scale.
We combined data from a network of over 3000 farmers (DEPHY Farms) who voluntarily
committed to reducing their use of pesticides, and the French Land Parcel Identification
System (FLPIS). Data from the DEPHY network have been collected annually since 2010 and
provide information on farm location, cultivated crops and yield, farming management, and
the levels of pesticide use through the Treatment Frequency Index (TFI). The FLPIS is a Frenchwide database reporting information on the geographical coordinates of the fields, their area,
cultivated crops, the type of management (organic or not) at field-scale. It is based on farmers’
declaration for the Common Agriculture Policy subsidies. In the FLPIS, each field is attached to
its farm through a unique identification number. More than 80% of the French farms are
represented in the database, and since 2015, farmers have reported the species mixtures. For
this reason, we only used data starting from 2015 until 2020.
These databases provide information on the distribution of species mixtures cultivated in
France and the related TFI levels. We compared the TFI levels of different species mixtures
with those of corresponding pure crops. For example, grain species mixtures (e.g., wheat,
barley, or triticale mixed with pea or faba bean) and annual fodder mixtures (e.g., triticale,
oat, and pea) were compared with pure wheat, and rapeseed undersown with companion
crops were compared with pure rapeseed. We assigned each farm of the FLPIS to a farming
System (e.g., arable or livestock farming) based on the type of crops cultivated.338
We found significantly lower TFI for crop mixtures when compared with those of pure crops,
confirming that crop mixtures are an effective lever to reduce the use of pesticides. Results
indicated that from 2015 to 2020, the French arable land area cultivated with crop mixtures
increased, diffusing from hotspots. Organic agriculture is a strong driver for crop mixtures but
is not the only one; in fact, livestock systems turn out to be strategic to foster crop
diversification. Indeed, grassland and fodder mixtures, directly used to feed animals, are
currently the most widespread species mixtures in France, thus explaining that in some French
districts, more than 90% of crop mixture areas are cultivated in livestock systems. On the
contrary, cereals and oilseeds, primarily used in transformation processes, appear harder to
value as mixtures.
Lechenet et al. 2016. Profiling farming management strategies with contrasting pesticide use
in France. Agricultural Systems.
Domaines
Sciences du Vivant [q-bio]Origine | Fichiers produits par l'(les) auteur(s) |
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